advice

[Bud]

well I heard that over ariating will release too much cO2 and cause my ph to climb too much heres my senario,2 hydro sponges(IV) in a 75 gal with at least 40% water change every day or every other(dont know which is the better of the two),6-7 3"discus and an aged ph of 7.6
thanks for advice,Bud

[aalbina]

Aeration of water in a fish tank does speed the release of carbon dioxide that is dissolved in water. It only "speeds up" the release - it will precipitate out of the water anyway - it just might take more time. In 85F water - that is not aerated - I would be surprised if it wasn't stabilized in 24-48 hours on it's own. The release of CO2 may change your pH value in the water - but it depends on how much dissolved CO2 is in your water to begin with. Either way - aeration or not - if there is a lot of dissolved CO2, it will precipitate out and change your pH. Sometimes this change is dramatic and big changes are not good for your discus. As an example, I have well water from deep wells in New England. In the cold months I have lots of dissolved CO2 in my water. pH out of the tap in the winter is about 8.2. After 24 hours of heating and aeration it's stable at 7.4 and remains at 7.4 from that point forward. So I also "age" my water - heat and aerate it in a storage tank for 24 hours prior to putting it in my discus tanks.

I see you report and aged pH of 7.6 - so I assume your aging your water. What is the pH before and after aging? Once the CO2 is dissolved out - its pretty much dissolved out. If your aging - the effects of gas off on your pH once the water is in your tank should be minimal. With 2 hydros - I wouldn't think you need an more aeration then you have.

With Juvies, you're probably feeding them a lot. I would probably opt for the 40% every day until they are adults but you have to do what your schedule and time will allow. IMO 40% every day is a minimum - I do 80-90% everyday but I only have a couple Juvies growing out in a 29 not my main adult tank so it's not that much water. I have a 55, a 29 and a 10 hospital tank right now. I'm changing 60 gallons a day right now on all three! Pretty small numbers compared to what some folks here are doing.

Adam

[Jhhnn]

If the PH of your aged, aerated and heated water has stabilized before adding it to the tank, no amount of aeration will change it. This assumes you're not injecting CO2 in a planted tank.

Aeration increases oxygenation, which is all around good for your fish and for the beneficial bacteria in your filters.

[Bud]

thanks guys good answer (just what i wanted to hear)!!!but ya, last i checked my ph was around a 6.8-7.0,and i wish it would stay that way!Im just growin out though(for now)heehee

[jimg]

Adam, just curious about your ph readings, if co2 is in the water it will lower the ph, when aerated and co2 is released it will raise the ph. did you mean yours is 7.4 from the well and 8.2 after aerating?

[aalbina]

No - it drops. It has for 10 years.

Adam

[Bud]

youre lucky Adam,mine starts at 6.8 ends at 7.6!!Im looking into that electronic water sofener someone(sorry i forget who)posted on here 150 $-3 year warranty easier than RO and doesnt strip minerals. Just wrap magnetic wire around incoming water line and plug it in (very low voltage too)

[Eddie]

youre lucky Adam,mine starts at 6.8 ends at 7.6!!Im looking into that electronic water sofener someone(sorry i forget who)posted on here 150 $-3 year warranty easier than RO and doesnt strip minerals. Just wrap magnetic wire around incoming water line and plug it in (very low voltage too)

7.6 is great. Many here keep them in higher with great success.


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[aalbina]

Hmm - you got me thinking jimg.

KH(degrees) = 0.056 * KH(ppm)
CO2 = 3 * KH * 10(7-pH) (KH in degrees)

So for me:
1.008 ppm CO2 = 3 * 3.36 * 10(7-8.0)

That's a very low CO2 level coming out of my well (if that calculation is right). I don't know if that's typical of deep well water or if all this chemistry stuff is right. But it does make sense - and jimg is right about CO2 gas off increasing pH a bit as the carbonic acid precipitates out - assuming CO2 is the only variable. I could have other salts that are precipitating out during aging that may lower the pH (calcium carbonate, magnesium carbonate). The trouble with TDS (mine is 150 after filtering), is that you don't know what the dissolved solids actually are.

I also filter through HMA (not RO/DI) so that could also be removing some alkalinity and causing the drop in pH as well depending on what is being taken out. So - I answered a bit generically that ageing will change your pH due to CO2 gas off to the original OP, but then using the example of my water was a bit counter intuitive without the whole story on my water - hope I didn't confuse anyone.

With such a low KH as I have - I'm considering using a buffer to keep from crashing - although my water change regiment is pretty heavy duty right now.

Adam

[Eddie]

Hey there Adam, my KH is also near zero. With the amount of water I change regularly, I've never needed a buffer BUT now that I am only seeing my fish weekly, I do use a buffer. Its the same stuff I use when I go out of town for 30 days or more.

[aalbina]

No - it drops. It has for 10 years.

Adam

Jimg - just tested again and I was wrong. I did mean it the other way around. It does change a bit winter to summer but your right - I had it backward. Don't know why I thought that... I did some calculations on CO2 a while ago and posted that above. I don't have a lot of CO2 in my water ... But I have other stuff that changes my pH after aging.

Thanks for the catch - hope I didn't confuse anyone! Been working way too long hours the past three weeks!!

Adam

[jimg]

My curiosity had me going I was about to spend hours again reading water tables/charts to see if I had it wrong!

[aalbina]

Glad you caught it! I have a vacant position at work so I am doing my job and the vacant position until I can fill the - too many hours has my brain fried.

Adam