pH of ro/di and tap water blend

[kss2801]

Hello,
I have set up a 40 gallon breeder tank and have used about 75% rodi to 25% tap water, this gives a hardness of about 60ppm. I just tested pH, I got 5.5 for my stored RO and 7.5 in my tank, with the blend. I want to lower the pH, do I need to use something like pH down or use more RO? I know more RO would lower the buffering capacity of the water, but does it also lower pH long term? Or does the pH of what ever you mix it with dominate, because of the lack of buffering capacity?

[ericatdallas]

Lack of buffering capacity means the pH will swing more. I think you're right about it going lower, but there is a possibility it could go higher. It really just depends on what the "contaminants" are in your tank.

I'm not an expert on water issues by any stretch of the imagination, but I follow the school of thought of "don't mess with a good thing" unless you know why you're doing it.

What is the reason you want a lower pH? My water out of the tap is around 7 and I don't mess with it.

Some people in the saltwater tank community like to use citric acid as both a dechlorinator and a pH down, but there are some risks. To do it right, you do need to add some "buffers" to make sure it's a controlled adjustment.

[kss2801]

I want to lower it to get my fish to breed. I have had them in the tank more than 1 month now and they have shown no interest in breeding. They are a known breeding pair. They are very healthy and eat great and are active. I have the temp set to about 86F. I'm feeding beef heart, bloodworms, tetra bits and nutrafin max. I don't know what else other than pH that is a bit off. Is there any thing else I can try?

[ericatdallas]

I'm going to have to punt there because I haven't done any discus breeding yet.

From hanging out in the forums though, if you're messing with parameters too much, that could stress them.

From breeding 'other' cichlids (and hopefully I'm not overstating the obvious for you), I would also check:

1) Water cleanliness
2) Are they acclimated yet? How long have you had them?
3) Traffic around the tank - high traffic = stressed fish
4) Lighting
5) Proper breeding surface, do you have a breeding cone? A surface to lay eggs?
6) Water flow (minimize it).
7) Other fish?
8) Basically, stated in some form above, do your fish feel safe?
9) Live foods get a lot of fish going. Sometimes people get all sorts of fish breeding with live worms, brine shrimp, etc.
10) Again, not necessarily applicable to Discus, but a lot of fish respond to environment. Sometimes high temperature followed by sligtly cooler temperature can get them going. Try keeping the tank at 86F, lower it to say 84F and fill the tank about 1-2 degrees cooler.

Again, 1-10 aren't necessarily discus specific, but are all things I consider with other species.

[jimg]

The water is fine for them. I would lower the temp to about 83. do large wc's with water a couple degrees cooler. and see how that goes. I have waited a lot more than a month for some pairs!

[kss2801]

Thanks for all the help. No worries about stating the obvious, better to cover all the basics.
I have a breeding cone in a dedicated breeding tank. Just an air sponge filter. They are definitely acclimated, I've had them maybe 6 wks now. Low light, low traffic. No live foods though.
I will try the temperature thing and see how that goes, then just wait I guess.

[Sean Buehrle]

Yep pound them with water changes every day, big ones.
A couple degrees cooler, it drives em crazy.
If anything has been proven around here, its that discus will breed in any water.

[nc0gnet0]

Lower the temp to 82, don't worry about the Ph, it is tds you want to be concerned with. I prefer a tds in the 40-50 ppm range, other people with different water chemistry might be a bit higher or lower. Than, as others have stated, daily large water changes with slightly cooler water. This is even more effective if you can time in with an incoming storm front (falling barometric pressure).

Rick