Boot282

Link to the light you are using? Stand looks great too!

Ryan, To answer the questions first. Standard 75 gallon tank. FX-6 canister filter. CO2 diffuser ceramic disk from Aquarium Co-op placed under the output of the filter. Simplicity and consistency is why I'm thinking of changing to sponge filters in this tank. I currently have 8 aquariums set up and use sponge filters in all but this one and one other. The FX-6 is a great filter except when it needs to be cleaned. Changing everything to air powered sponge filters saves me the canister cleanings and probably saves me some electricity expense. One of the valid points you bring up is on the current I would be losing with sponge filters. I will need to consider that if I switch out the canister. The reference to Tom Barr is great as back in the early 2000's or thereabouts he shared a ton of knowledge and helped many (including myself) achieve success in planted aquariums. The over thinking is true - the math is probably way off but it was a fun way of thinking about my original question of how much CO2 is really lost with surface agitation. And finally, will take your advice and adjust that needle valve accordingly to compensate for the loss if I do end up with sponge filters in this aquarium.

Congrats. Super exciting seeing first hand your own fish spawning - Never gets old.

I usually pair an inexpensive heater with the Inkbird 306-T. The probe on the 306-T is rubberized and can be submerged constantly. I currently use 5 Inkbirds that have been running flawlessly for a couple of years on 5 of my larger tanks. My only complaint is the suction cup used to hold the temperature probe to the side of the glass is crap. I purchased them on eBay for around $25 each. Gives me piece of mind that I won't cook my fish.

Antichton, I appreciate the well thought out response and the link – From what I have read in the past and reading the info you provided along with the info in this link, https://www.2hraquarist.com/blogs/choosing-co2-why/how-to-push-the-limits-of-co2-safely it seems to me the larger the bubble (and fewer of them for the same volume of air), the less efficient in creating surface agitation (for gas exchange). For my purposes this is a good thing. I’m going to assume running a sponge filter (at my typical rate) without an air stone produces a bubble that is about ½ inch in diameter when its breaks the surface (due to the pancake shape). The surface area of each bubble would be about 0.2 sq in. I would estimate there’s only room for about 5 bubbles per inch of height. Using your example of a 20 high, the bubble surface area would be 0.2 (sq in.) x 5 (# of bubbles per inch) x 16 (height of the tank) = 16 sq in. which increases surface area by about 6%. This falls well into my acceptance of how much the CO2 loss increase would be using sponge filters vs a canister. Hopefully, there’s enough errors in here to cancel each other out producing a somewhat accurate result!

Thanks for the reply FriendlyLoach. I've also read there is some CO2 loss but I wonder how much there really is. If it's a small percentage, it would be worth it for my situation. I'll search around and see if I can find real numbers.I

I have a heavily planted high pressure CO2 tank I'd like to change the filtration to sponge filters from a canister. Anyone have experience with the CO2 loss by adding air to the tank? Wondering if the loss is enough to be concerned about. Thanks for your reply.