ZRDR 2L Co2 Generator System with Pressure Gauge Automatic Pressure Relief Valve Bubble Counter for Aquarium Plants，Stable Output

UPDATE April 24, 2021 - I have now been running this set up for a few months now and it is awesome. I change the baking soda and citric acid about once every 2 weeks. The output has been consistent and the issues I had at first with the gauge not showing accurate readings is no longer an issue. My plants seem to be doing really well. I highly recommend this set up and have changed my rating from 4 stars to 5. Original: Once set up, I so far have found this CO2 setup to be awesome. Here’s some tips from my experience, step by step: 1. My cotton filter was already attached to an apparatus that looks slightly different than the one in the directions (part 3). My set came with a spare cotton filter also (part 4). 2. Screwing the filter (part 3) to the valve (part 2) was easy in my experience. Just tighten as far as I could. 3. Use the funnel and fill the tank (part 1) with ingredients. NOTE: 200g is 7/8 cups. I did about 3/4 cup each citric acid and baking soda, then 1 cup water. I will do 1 full cup each acid and soda and 2 cups water next time. I was short on supplies. Screw the pressure valve into the body as tight as you can (part 2 into part 1) 4. My valve did not register any pressure to start. I waited a long time. Finally I gave up, unscrewed the top bolt above the gas output knob on the valve and heard air escaping. I knew then it was producing fine. I never reused this top bolt once removed. 5. Connected the solenoid valve (part 6) and used the wrench (part 13) to tighten into place securely. 6. I screwed the entire top ( smaller end with bolt) of the bubble counter (part 5) and filled 3/4 with water. Replaced the top of the bubble counter tightly and screwed the other side (bottom) in place tightly to the top of the solenoid. 7. Removed bolt from top of bubble counter and slide end of rubber tubing (part 17 - “trachea” in instructions is tubing) they the home of the bolt. Then push the end of rubber tubing onto the top tapered part of bubble counter where the bolt was and re-screw the bolt on tightly to hold tubing in place. NOTE: The tubing is stiff and pretty hard to work with. I am considering replacing it with higher quality, more pliable tubing. 8. Cut rubber tubing twice —Once about 4 inches from the bubble counter (save this 4 inch section for later). The second cut about a 18 inches long. 9. Secure the check valve (part 12) on the other end of tubing that’s attached to solenoid (end with filter inside of check valve goes on this end of tubing) tightly. The loose 18 inch section of the cut off tubing gets secured in the other side of the check valve (open end of the valve with no filter). 10. Secure the other end of the 18 in section of tubing to the u shaped tube (part 14). This part will go over the edge of your tank when you install it. 11. Use your remaining loose 6 inch section of tubing and secure it tot he other end of the U shaped tube. The other end of that 6 each section secure your atomizer (part 15). The CO2 set is now ready to install. Put the base on the bottle (part 16) and put it wherever you plan on storing the unit. Secure the U shaped tube over the edge of your tank and use the suction cups (parts 11) to secure the 6 inch section of tubing between the U shaped tube that’s now over the edge of your tank and the atomizer into place inside your tank under the water. Plug the solenoid connection valve (part 8) into the solenoid, then the power supply cord (part 7) to this. Once everything is in place, plug the power cord into your outlet to power the solenoid on. VERY slowly turn the gas output knob on the pressure reducing valve (literally a hair width at a time) until you reach the goal of one bubble per 10 gallons every 5 seconds or so. This process took me a while to adjust but once I had it set it’s stayed put. The set up day my pressure valve showed no pressure. The bottom of the stainless body got very cold and my bubbles were producing a set count so I knew it was working fine. Figured the valve was faulty. The next day though it reached 10-15 or so in the green range. I plugged my power plug into a wall timer and set for 8am to 6pm. Takes about 30 min in the morning for it to fully come back up to pressure. It is very consistent so far throughout the day. Also, I agree with other reviewers that the solenoid does get quite warm. Mine doesn’t get HOT as others have described but it is pretty warm to the touch. I will be keeping an eye on it as well as the bubble counter evaporation. Last note: the first set I received was missing the u shaped tube, suction cups and the replacement filter cotton. I contacted Amazon and the provided a replacement which was fine. I sent the first incomplete set back for a refund. The missing parts, minimal instructions and questionable valve readings are the reason for only a 4 star rating. So far so good though. I will update if anything changes. I do recommend and hope these more detailed notes will help explain the set up process better than the minimal instructions that are included with the kit.

ZRDR Aquarium Co2 System 2L with Pressure Gauge Automatic Pressure Relief Valve Bubble Counter Purchased 20 May 2024 from ZRDR for $77.99 WARNING: SERIOUS INJURY OR DEATH CAN OCCUR, DON'T DO THIS This is a nonstandard use of the ZRDR CO2 system. This is more of a product suggestion than a review. For the price, this kit is outstanding for the original intended purpose (aquarium) IMHO. This modification is not for the risk adverse, feint of heart, uneducated, nor unskilled. I am merely illuminating what I have done in the hopes that ZRDR will make a professional system for the masses (product suggestion). In the beginning...there was the SodaStream Art by Pepsico. Then I converted this thing to replace the Art and gave the Art away. I just didn't want to fool around with their reasonable $15 60L CO2 canister exchange program, preferring to make my own CO2 from reactants (baking soda and citric acid). I mean come on, making CO2 is cheap and easy. Upfront investment cost is about the same. Recurring costs can be less, providing local access to low cost reactants. At 200g per charge, 5lbs is 2268 grams yielding 11 charges. For convenience, the reactants are sold right here on Amazon: https://www.amazon.com/gp/product/B000OZFECU/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1 https://www.amazon.com/gp/product/B0774M73SF/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 This project does require know how and mechanikin' skillz. There are two basic options, modify this canisters OEM top cap permanently destroying the built in regulator and removing everything past and including the bubbler (port in cap for bubbler is 1/8" BSPP), or drill and tap an M30x1.5mm plug using a ~34x28mm O-ring: https://www.amazon.com/gp/product/B0BCFB7PBV/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1 Then it's basic plumbing parts until the bottle. I clear Epoxy all plumbing joints. I used two ball valves and a pressure gauge so I could check the canister and bottle pressure, all 1/4" NPT. Then a pressure washer quick disconnect: https://www.amazon.com/gp/product/B07RHK7HK2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1 https://www.amazon.com/gp/product/B08F2X5L24/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1 Then drilled a replacement SodaStream bottle cap with 3/8" brad point drill bit then 13/32" and thread with 1/4" NPT tap, appropriate washer threaded 1/4" NPT, epoxy and a 1/4" compression fitting: https://www.amazon.com/gp/product/B0CZ32LWCC/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1 And a check valve between pressure washer QD and 1/4 compression fitting: https://www.amazon.com/gp/product/B0BN6HL5B3/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 Then there are two options for the 1/4" stainless tube. From the underside of the bottle cap to the end of tube assembly should be 3+1/2 to 3+5/8 inches long. Easiest was to use a piece of this tube and crimp end in vise for small holes ~1mm: https://www.amazon.com/gp/product/B0006NAUQK/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1 Fill Sodastream bottle with water to line, chill in fridgedator, screw on and three *quick bursts. NOTE: releasing Sodastream bottle pressure between each burst (I just unscrew bottle from cap). At the end of each burst the bottle pressure should read ~55psi. I should have added a 55psi regulator. This is INHERENTLY DANGEROUS as the Sodastream bottle can be pressurized to way more than 55psi. The second method for the tube assembly that I preferred was to use heavy wall (0.065" wall) stainless 1/4" tube, drill and tap for 3/16-24, then use a vented socket head stainless screw (0.046" hole = 1.1684mm). Both purchased elsewhere. Sodastream bottles and caps here: https://www.amazon.com/gp/product/B01AHGDQ3Y/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 https://www.amazon.com/gp/product/B004OYMOK2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1 Amount of CO2 in soda is amazing. I get 6 to 10 1L carbonized Sodastream bottles out of a single baking soda and citric acid charge. At 11 charges that is at least 60 1L bottles carbonized, up to 110. When ZRDR canister pressure drops to below 100psi, I pressurize the Sodastream bottle assembly, then QD and shake vigorously for 10-45 seconds, let sit in fridge for a bit to get more 1L carbonized bottles out of a single charge. This is the reason for the QD and check valve on bottle cap assembly. I like this method for many reasons, the added bonus is it doesn't leak so CO2 waste is minimized. But it lacks a safety release and regulator making it INHERENTLY DANGEROUS. Some notes: I did some research and lots of R&D on this project. What I show here is what I ended up with that IMHO works best. DO NOT use more than 200g of baking soda, 200g of citric acid, and 300g of water in this canister. Pressure will build to 270psi (room temperature) after a couple days unless you use some of the CO2. The canister safety release built into the OEM top cap is advertised for 30Kg/cm2 which is 426psi. My method shown here eliminates that safety release which is DANGEROUS and NOT recommended. I should have added a 300psi 1/4" NPT safety release sold right here on Amazon. Ordinary soda bottles have a burst pressure of 12bar which is 174psi, though there is yielding way before burst, I do not use ordinary bottles. Sodastream bottles are heavy wall and burst has been tested (one unit) at 25bar or 362psi, though there is yielding way before ultimate. Pepsico says this: "To successfully carbonate water with a CO2 tank, the gas regulator valve should be set at 55 PSI, to enable the serving pressure to remain at around 12 PSI." I should add a 55psi regulator, this method is dangerous as the Sodastream bottle could be pressurized way above 55psi. Pepsico advertises 4 years per Sodastream 1L bottle, not cycle dependent. The modification I made to the Sodastream bottle cap invalidates all of this. It would be best if a cap was specially made for this application (product suggestion). edit 23 July 2024 I ended up replacing the vented screw with a 0.8mm misting nozzle. Taking the misting nozzle apart and removing the spring and rubber check valve. This works much better. FYI 0.6mm is too small. https://www.amazon.com/gp/product/B093L385FF/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1 Also, I purchased a used 5.5L tank elsewhere and added an oxygen regulator, but that bottle needed a smaller o-ring stretched on the M30x1.5mm top cap, 1"ID by 1/8" thick. https://www.amazon.com/gp/product/B073P1C18S/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 Notes: Helps to put glycerin on the o-rings. Helps to put a small 5" balloon in the tank and fill with water (ye old brass hose nozzle) then drop in tank and screw on top cap. Then shake. Balloon comes later for reuse. https://www.amazon.com/gp/product/B07SR1P15T/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

Out of the box it had issues holding pressure, discovered the valve for the main assembly leaked, was able to get it to hold and it worked fine for about a month but would only last 3-4 days before I had to re-fill, far under what I would have expected. Failed today 100% and the valve is now broken. There is pressure stuck in the tank but the release valve that goes to the aquarium is stuck and I can't easily unscrew the hookup without having a lot of pressure blow back at me so I'll have to try to disconnect it somehow to relieve pressure or hope it leaks for a week and is safe to handle when the pressure gauge goes down. The thumb screw for the pressure valve rotates freely but it only opens the valve between the aquarium and the open air, the pressurized tank is still stuck under pressure with no way to easily open. Could be a safety issue if someone were to overfill this and had no way to vent pressure without unscrewing the top (I don't even think there's a pressure valve that I was able to spot)

This is an excellent generator, though it took me a bit to set up. I did DIY CO2 with yeast and all that and what a nightmare. Always leaking, weak output, nothing but hassle from start to finish. This is what I wish I knew before I started. Maybe it will help someone. This is much better than DIY. Much. Totally worth the cost, albeit higher than DIY. There are some things you should know that the directions aren't clear on. Firstly by filter cotton they mean a hard white ceramic circular thing. There's no actual cotton. It feels a bit like an airstone and is connected to a stainless steel tube that screws on to the main lid part. There is some confusion on the diagram. Yes it is different when it talks about connecting that filter "cotton." Don't worry about it. Just connect it to the bottom of that lid part. Also, there is a part in the instructions that is missing on the latest version but it's unnecessary so don't sweat it. The bottom line is the diagrams in the directions aren't always exact to what you will be looking at. It's not a big deal though as it is pretty intuitive to put together. The other thing I wished I knew is how fast you need to shut the lid on once you mix the active ingredients. Once you add that water to the soda/citric acid it will feel like a strong wind coming out of the bottle. The first time I did this I didn't put the lid on fast and then my pressure would not go past 1. It needs to get to 10. Slam the lid on as fast as you can and screw it down immediately. If you don't, the pressure will all release and you won't get anything to register on your valve. Use a cup of baking soda and a cup of citric acid. A note, be sure to tighten the regulator all the way to let the pressure build up before you put the lid on. Only loosen when you are ready to start using the CO2. It is normal for the bottle to be extremely cold once you mix the ingredients together in it. Good things: - One amazing thing about this generator is the fact that you can connect it to a timer via the Solonoid. This is HUGELY helpful because you can turn it off at night and avoid gassing your livestock. - More economical than getting replacement bottles of premade CO2 - Lasts a long time before needing to be remixed with new ingredients (2-3 weeks seems to be the duration) - Has a built in drop checker - Has a nice stand to keep it from toppling - Nice pressure meter lets you know when it's time to change it Bad things: - Directions aren't up to date with the current product they are shipping, resulting in a bit of confusion - The drop checker, at least on mine, is a bit defective in that all the water goes away within about 2 days. Not the end of the world because the main thing is to use it while you regulate the output during setup/refill - Customer service is not the most responsive. They left me hanging on this drop checker issue. Overall I'd definitely purchase this again. Great kit.

Let me start off my telling you that one of the pieces didn't fit properly. I am still giving it 5-stars due to Amazon and the seller's responses to the situation. The build quality is great. The tank is sturdy and although has a lot of Chinese language stickers on it, doesn't take away from the steel quality. I chose this one because it looked similar to other tanks but this was the cheapest option. This also comes with a solenoid that is working great. (To those that don't know, solenoids are connected to your timer (sold separately) that helps you to turn on/off the CO2 at specified times) The part that didn't fit was for a filter inside. There is a Tertiary filter that I think is supposed to block off small particles that can go up into the hose (I don't know how often that happens because it's supposed to convert it into gas) but I'm assuming they put it there to prevent that from happening. The problem is, the threads on that filter do not fit with the valve. This is why I contacted the seller and Amazon. They worked with me to bring some resolution and so that is why I kept this at 5 stars. I don't know if I got a one-off or if this is a common problem in other ones too. I would normally take one star off for these cases but to be honest, I don't even think that the filter is needed. I tried the rest of the set up and let me tell you, this CO2 Kit is GREAT. I had a Fluval 25g CO2 kit but that lasted me all of 3 days before the CO2 was gone. I then looked up replacement tanks and they were super expensive. So expensive that I decided to look at other options. Everyone recommended DIY kits which I was going to do - but they looked so tacky with the plastic 2L bottles and such. Anyone on the fence about purchasing this, I can tell you, pull the trigger. This has been a GREAT replacement for me and the twist valve to control the BPS works GREAT. SO much better than the fluval one that would just burst my hoses. This can let you tweak from 1 bps to .25 bps EASILY. It has so much better control. Also, making the CO2 is as easy as putting 200g of Citric acid, 200g of Baking Soda and 300ml of water and screwing on the valve. Set up is so easy and they have step by step directions, which surprisingly, are legible (many of these imported from China stuff have horrible directions). All of the other components are of great quality. This is the longest review I've probably written but I really wanted to give Amazon and the seller props for working the situation out with me and also wanted to say that the product quality is really good. I hope that I had a one-off situation with the filter (but again, the filter doesn't seem to be a necessity) and for the price, it is really a good deal.

So far, I like this device and it is super sturdy and looks seriously tech. It really turned out well and was very easy to install. I used the instructions for the dose of chemicals needed, but used the video here on Amazon to get everything connected right. I don't know how many CO2 bubbles I need, but I got it running. You may need a short extension cord which I did as I didn't have it close to a plug outlet. It's a two prong for those of you who want to know. I got it up to the psi that it said and then started putting everything on it like the video showed. I was a little paranoid about cutting the plastic hose air cord but then finally just chose my location which was at the back and figured out where I'd put the in between piece. FYI - the steal curve to hang the plastic didn't work on my tank as it's a black rim 120 gallon and too thick. Luckily, the bubbler piece is heavy so I didn't need it. Oh, make sure the bubbler piece is screwed on snug unless you want a giant bubble which I corrected.. Note - do not put it near an intake as it will fill up your filter with air! I have it on the end with my out take of my canister filter. Fish aren't disturbed by it. I needed CO2 for my plants as I'm getting a lot of algae and my plants needed a kick to grow better. I didn't want to fuss with gas. I admit that my first try sorta failed. I don't know if I mounted the top part with the gasket wrong but it [the gasket] popped out. I lost all of my gas from the first batch and tried again [so buy yourself some big bags of the chemicals or you'll hate yourself and get frustrated], but I used one of the spare gaskets in case the other one was a little odd to try the second time. It's now working perfectly! I am running a serious bubbler with air so that when my lights turn off I don't accidentally hurt my fish. I read that can happen. So far, so good. Once my plants are seriously growing I'll try posting a picture here to show the end results.

EDIT 3/31/2025: Seller reached out and offered a replacement regulator, great customer service! The new regulator has been redesigned to not include the working pressure adjustment -- which is what broke with the old regulator. This gives me some confidence that this regulator may last but only time will tell. I set it up and it has been working for 3 days. Attached a photo of the old (the one with the black adjustment cap) vs. new (the one with no black adjustment cap) regulator design. EDIT 3/24/2025 I disassembled the broken regulator and there seems to be a problem with the mechanism that controls tank pressure being released into the working pressure chamber. (I've attached photos of the disassembled regulator to help illustrate this) From my observation is *seems* the way it is supposed to work is as you screw down the black working pressure adjustment cap, it pushes down on a plunger which opens a spring loaded valve to release co2 from the tank. No matter how tight I screw on the cap, the plunger is not able to open the valve enough to release pressure. If I use tweezers I can manually press down on the spring loaded valve and release co2. With that said, it seems like a bad design --as the plunger is obstructed and unable to fully opening the spring loaded valve. Original Review from March 2025: Worked fine for a few weeks when one day I noticed the bubbles stopped flowing and the working pressure read 0psi while the tank pressure read 500psi. At this point I closed the needle valve and over the next 24 hours the working pressure went back to 50psi but immediately fell to 0psi when I reopened the needle valve. I took the risk and managed to unscrew the regulator from the tank while at 500psi. This confirmed there was still plenty of pressure in the tank as it took about 10 minutes to release all of the CO2 from the partially unscrewed regulator. I inspected the regulator for any obvious signs of damage but did not see anything. Refilled the tank and tried again. It worked for about one week before the same thing happened. Now I am stick with a tank at full pressure and I'm scared to try to open it again and not even sure how to safely dispose of it . I've posted on Reddit and Facebook for help and multiple other users experienced the same problem. Also look at the reviews for the ZRDR regulator on Amazon and you'll see another report of the same issue. Complete waste of money, time, and quite dangerous. I've attached a video demonstrating the pressure drop.

This Co2 generator is honestly fantastic. It produces a long lasting amount of co2 and holds a steady rate of bubbles into the tank. I have one of these bottles on my 20 gallon long aquarium, I had it set at a bubble every 2 seconds for 10 hours a day, the bottle lasted for 1 week shy of 3 months. I fill mine with a ratio of 3/4 cup of citric acid to 3/4 cup of baking soda to 1 cup of cold water. My 2nd bottle that I purchased had a leak coming out of the solenoid, upon taking it apart I found that there is a little screw that goes into the bottom of the solenoid block that had a bad gasket, I added some Teflon tape to that screw and screwed it back into the solenoid and now it has no leaks. You cannot beat the price for this co2 generator, it lasts a long time and has a reliable and steady stream of bubbles once set. The only time you need to adjust the bubble rate is when you set it up after filling it or when the co2 pressure gets really low.