What can buffer pH?

[Ringo]

My RO water comes out with a pH of 6 max, TDS is 0, and KH and GH are less than 10, lowest measureable amount on test. However after 8-12 hours the pH is at 7.2!!!!!!!!! Other measures are still the same. The house does have a water softner installed, so water first goes through the softner then to the RO/DI unit. I'm using RO water for my breeders.

Thanks for any help.

[judy]

Your Kh needs to be at least 4 to keep the Ph from bouncing.

[Ringo]

So, the pH of pure RO water will constantly change?

[judy]

Most people who use RO water mix it with tap before adding to the tank, to achieve the stable water parameters they want. And the water softener is not helping at all. Can you bypass it for the fish tank water?

[Graham]

The move around would be from CO2/O2 exchange and the small amount of KH that was present...as the CO2 gassed off the KH/O2 would allow the pH to rise...

G

[Don Trinko]

There is so little TDS in ro water that any small amount of acid or alkaline will move ph drasticly. Even the test liquid will change the ph so it is useless to test ph untill you mix it with other water or chemicals. It is also bad to use pure ro for fish because the fish excrement, excess food etc will change the ph. Don T.

[Ringo]

Thanks for the replies, the problem I'm having is even with a mixture of 80/20 RO/Tap the pH is 7.4 and the KH is around 20. I would like to get the pH to 6.6-6.8 but this doesn't seem possible, because if I use a mixture of 90/10 the the pH will be unstable. Even at 80/20 the pH will be unstable. Maybe I will try a mixture of 60/40 to at least get the KH up to 40 and see what the pH comes out too. If it turns out above 7, should I just use buffer? This just seems very strange to me. Thanks again for your replies.

[Graham]

Whats wrong with 7.4...you'll drive yourself nuts chasing magical numbers...lots of hobbyist have discus in 8.0....mine live in 7.7/7.8

[Ringo]

Graham will a pH of 7.4 be ok for breeders? Believe me, I'm about ready to just say forget trying to get it to some specific number and just mix 70% RO with 30% tap.

[Graham]

Lower would be better but there are hobbyists on here that do it in higher pH's....Stability with water parameters is more important that the numbers

[Don Trinko]

The same thing that keeps your ph stable (KH) also makes it hard to change the ph. Discus will do fine from less than 6.0 to more than 8.2. I have had fish since the mid 50's ( 1950) and have attempted to change ph on various occasions, all unsuccessfull. It can be done but it's not worth the trouble (or neccisary) unless you are breeding discus.
Don T.

[salth20]

I wish I could get my PH to 7.2 . Where I live the water is incredibly hard.. over 8.0 . I originally filled the tank with straight tap for a fishless cycle. The bacteria haven't minded a bit, and the cycle is complete. I have been working for 12 days now to get the PH down. I'm still at better than 7.6, even with 5 gallon daily changes of RO, and additions of Acid Buffer from Seachem. Over half of the water is now RO. I also ran a water softener pillow for two 48 hour cycles, recharging between uses. It actually worked really well, bringing the KH from 150 ppm to between 50 and 75 ppm. The breeder I have selected to purchase from has his tanks at 6.8 , and recommends I am close to that when the new kids arrive. Maybe I'm chasing a moot target, but this is my first discus tank. If possible, why not give the fish as close as possible to their natural requirements? In some respects, salt was much easier... The PH will pretty much always be stable from the buffers in the salt mix.

[brewmaster15]

Hi salth20,


Maybe I'm chasing a moot target, but this is my first discus tank. If possible, why not give the fish as close as possible to their natural requirements? I think you may have just answered your own question...:)

You said "if possible" but before that you talked about how difficult its for you to get the water where you want it pH wise...


I have been working for 12 days now to get the PH down. I'm still at better than 7.6, even with 5 gallon daily changes of RO, and additions of Acid Buffer from Seachem. Over half of the water is now RO.


Fighting your water like this is hard now.. once you have discus in it...it'll be harder.
My advice...

If you really want that low pH.. Ditch all the water in the tank... use straight Ro water for most of the water and use maybe 10 % tap....play around with this % to get what you want... The way you are going about it will not be good for the discus and will drive you nuts... Its going bounce like crazy when you change water or add water.

You can also try 100% RO and reconstitute with something like RO Right,...

Discus will grow fine in the higher pHs...you need to watch tank hygene more as the pH rises...but many here have raised beautiful discus in less than optimal or natural pH's.

hth,
al

and ps...Welcome to SimplyDiscus...and the obsession:)

[LizStreithorst]

Brew gave you some good advice here. It's better to try and work with your water rather than fight against it.

[salth20]

Good advice indeed. I agree that managing PH is much harder with lives in the tank. The natural input of waste will continually drive PH down, and RO does little if any to buffer the decline. With no fish in the tank, I was attempting to get close to the breeders water parameters to give the kids a good start. Over a long period of time, PH fluctuations are inevitable, I just didn't want to add any more stress to the new arrivals. PH today is between 7.0 and 7.2 . I'm going to watch the tank for one more week. If I stay around a PH of 7.0, (and I think I will at this point), I'll be happy enough to contact the breeder, and have him ship next week. IMO, a .2 on the PH scale is negligible, well within the static range of the test kit alone. I developed a lot of patience when keeping marines.. another week with an empty tank won't hurt a thing.
Thanks for the welcomes, and advice... good stuff, keep it coming.