Question about PH

[jersysman]

I have a question about ph. I am going through a fishless cycle so I don't have any fish yet. I tested the ph of my tap water to see what it was while I am waiting. I put some water in a cup and sat it out for 24 hours. The ph in the cup was about 8.0. That is very high. I wanted to keep a community tank of fish, but isn't 8.0 high for community fish. I wanted some rainbow fish, dwarf gourami, pandy cories, and otos. Any way to bring the ph down?

 

[bzbee]

I asked my LFS if they did anything to their pH since our local water supply is also hard like yours (also pH 8 straight from the tap), and they never add chemicals. They do use natural means like driftwood and peat for more exotic species with higher margins. They pretty much only buy fish that have been bred in and are accustomed to the hard water. Check out your LFS and you'll be able to tell real quick what fish do well in your water. If it's anything like mine, you'll see lots of cichlids I've definitely seen dwarf gourami, panda cories and ottos before, so I'm going to guess you're probably okay. The problem with chemicals is that it subjects your fish to frequent pH swings, which are more stressful than a constant high pH.

 

[jersysman]

I have another observation. I hope someone can shed some light on it for me. I tested the water straight out of the tap. It had a ph reading of 7.2. I let it sit out in a bowl for 48 hours and took another test. This test read 8.0. Why would the ph go up from 7.2 to 8.0?

 

[BASSNMAN]

Your water probably has a high co2 content from the tap. When it evaporates out, the ph will go up. You can keep most fish at that ph. Stable ph is more important than a certain reading.

 

[megos1]

when you let water sit w/o anything live in it, the pH will continue to rise. putting fish in the tank will bring down the pH b/c they excrete ammonia.

 

[oxymoron]

I might be wrong, but I think ammonia from the fish waste would make it worse, pure ammonia has a pH of around 11-12 I believe.

 

[megos1]

ammonia is acidic, so it lowers the pH, it will neutralize with the high pH of the fishless tank water. it works out.

ps. welcome to the forum!!! what do you have for fish?

 

[mattrox]

Oxymoron is correct. Ammonia is not acidic. It Accepts H+ ion from acids to form Ammonium ions (NH4+) .... Ammonium ions(NH4+) act as an acid, it donates a H+ ion to alkaline substances, then forms ammonia (NH3)....

if you have a high pH ammonia will not neutalise it.

NH3 + H2O <--> NH4+ + OH-

 

[jersysman]

Thanks for all the help. I'm getting an RO system and hope that this will help my PH problem to some extent.

 

[mattrox]

Don't worry about RO too much and pH too much. Don't go looking for work to do, that is for sure.

8.0 would be ok for most fish IF it is stable, any higher might cause a problem. People keep Discus (in healthy condition I might add) in pH of up to 8 and although this is not their water in the wild they adapt well.

But if you are really worried........
The only thing I would like to know is your KH. If you KH is high then you could dilute with RO until you had a KH that was lower, but still provided buffering capacity. In which case to get to pH 7.5 you would have to dilute approx 1 gal of tap water in 5 gals of RO water. or 2 tap in 10 RO and so on. If you are accurate with this you shouldn't have too many hassles

HOWEVER, If something other than carbonate (ie KH is low) is causing a high pH then you may have little buffering capacity and using RO, while "fixing" the pH, also causes KH to drop and your tank may be then suseptable to pH swings.

Check out what your LFS uses, visit them every couple of weeks and see the conditions of fish. Often a LFS will order a huge number of some fish...dependng on what they sell.... Use these as an indicator of water quality. Keep an eye on those fish over the weeks and see if they suffer as a result of exposure to LFS water.

 

[jersysman]

I've already ordered the RO system. I was thinking along the lines of diluting it with the tap water as you suggested. A ph of 7.4 to 7.5 would be very acceptable to me. Our lfs is no help. I asked what the ph was in their water and they said that they don't even test for it. There was a college girl working there though who said that she uses an RO system for her tank. The water here is very hard, that I know. You won't even see suds in your washer when you wash clothes.

I;ll have to remember that 1 to 5 ration for RO and tap water.

 

[mattrox]

Remember that you should test the water you are goign to put into the tank each time to make sure it matches pH and hardness. Tap water quality can change with the seasons.

I hope the 1:5 works for you. Let me know.

 

[jersysman]

I'll be testing it. Once I get the correct ratios worked out, it shouldn't be too hard.

 

[jersysman]

HOWEVER, If something other than carbonate (ie KH is low) is causing a high pH then you may have little buffering capacity and using RO, while "fixing" the pH, also causes KH to drop and your tank may be then suseptable to pH swings.

I got my GH and KH test kit in today and just as I figured, they were both sky high. I don't know which reading to put on here, however, my KH was 12 or 214.8 ppm. My GH test was 14 or 250.6.

I definitely think RO water is called for here.

 

[mattrox]

You should be fine mixing RO to dilute the carbonate.

 

[jersysman]

Would mixing the RO and tap water be sufficient, or do I still need to buy the commercial products to put the minerals back into the water?

 

[mattrox]

I'd just mix, you would be putting back in what you just RO'd out anyway.