Ph???

[daopeter]

Hi, I need a little help concerning my r/o water. I currently have a 58 gal tank, 36x18x20 with Eheim 2215 canister and AC 110. Temp 84, Amm 0, nitrite 0, nitrate 0, tds 50, gh 1, kh 3. Water changes done 2x a week at 30% with r/o water with 10% tap water added. I have a thin layer of sand in the tank and 2 pieces of manzanita branches.

My question is why does my r/o water have a ph of 7.2 out of the unit. The ph is 7.4 when i add 10% tap water to it. I currently have a discus pair by itself in the tank. I thought the r/o water would be acidic. I am trying to reach a ph of 6-6.5. Would discus eggs hatch with a ph 7 or higher?

Or is it the kh? Is kh 3 too high? Confused...any input is greatly appreciated. Thanks

[jbree13]

ro water should have a neutral ph, so a ph of 7, as for the breeding I am not sure! but if they are domestics I couldn't see why they wouldn't, its usually water hardness that will stop the eggs from hatching because the sperm doesn't reach the eggs. Again I am not 100% sure since I haven't breed discus, this is just from reading books and online stuff

[josenestor]

daopeter,

I use RO water reconstituted with R/O right. I do maintain a pH of 6.3 - 6.5. But the reason I can do that is because I have a planted tank and I feed CO2. If I shut off my CO2 feed, my pH climbs to jsu above 7.

jbree is absolutely correct. Pure RO water has a pH of 7. What makes the pH of RO water dip below seven is the concentration of CO2 in the water. Aerating your water for a day before you put it in the tank may increase the CO2 concentration and dip your pH below 7. But the pH will eventually settle once the concentration of CO2 reaches equilibrium in your tank, possibly back to above 7 because of the tap water and whatever else you add.

People use all kinds of things to lower the pH: aquarium grade peat moss in your filter, almond leaves, driftwood. There are also pH buffering products out there. But chemically messing with pH is a huge risk and you can end up crashing your pH and killing your fish. I would experiment with natural ways like the ones above. But without CO2 injection, you may find mixed results.

Having said all that, many many people keep discus at 7.2, 7.3 and 7.4 without any issues at all. Some have been lucky enough to breed them at that pH. You are keeping your water quite soft and softness may be more important to discus breeding than pH.

Those are my two cents...

Good luck

[daopeter]

Thx for your responses. I didn't realize RO water had a ph 7. So I guess I don't need to lower my ph to 6.5. Good...less work for me. ;) As long as i keep soft water in tank I am ok. thx guys

[yim11]

Having said all that, many many people keep discus at 7.2, 7.3 and 7.4 without any issues at all. Some have been lucky enough to breed them at that pH. You are keeping your water quite soft and softness may be more important to discus breeding than pH.


I'm not sure it's luck to breed at 7.2-7.4 pH, because as you mention, it's not pH that is as important as softness.

[nc0gnet0]

Pure RO water has a pH of 7.

Define pure RO? Technically speaking pure water has no ph and is very unstable. What gives RO water its ph value is the trace amount of impurities still left in the water. I can get my TDS down to about 35-40 and the water maintains a ph of about 7.8 p 8.0, and discus will breed like mad in that water. PH is practically irrellevant (except perhaps with wilds).


What makes the pH of RO water dip below seven is the concentration of CO2 in the water.

It can be one of several things that can lower your ph. Tannins are another. Acids from almmost anything will do the same.

[josenestor]

I stated in my reply you can lower pH by adding tannins, which come from peat moss, driftwood, leaves, or extracts. I have tried these methods and found them little effective at maintaining desired low pH. For one, the fact we do so many water changes for the discus disposes of quite a bit of the tannins on a regular basis and replaces them with more RO water. I have heard of people maintaining low pH with tannins. I suppose you can add the tannins to the RO. I have not tried that and would have to test it. But I think you will find most people give up on the low pH strategy and give in to high pH. My pH stays between 6.3 and 6.5 all the time and can adjust it should my TDS change.

One more point is that tank contents can have pH buffering capacity, i.e., gravel, driftwood, plants, rocks, etc., up or down, of course.