lowering ph

[travelinman1969]

I recently had to stop using my R/O and had it taken out of my house. It wasn't producing water fast enough. Was only getting about 10 gallons a day. I plan to get a new, bigger one in a couple of months. I am now having to use the tap water and the ph is way up there at about 7.8-8.0. I need to lower it. I'd like to get it around 6.8-7.2 for my arowana. Since the ph has come up he's not eating as much. A LFS guy said baking soda diluted in a water cahnge would help. Never heard of this. Will it help? I have a water softner. Should I bypass it or is the soft water okay? This is the first time I've ever used tap water in this tank, so excuse the duh factor. :rolleyes:

[OrionGirl]

The water softener works by swapping ions--the water will have more dissolved stuff that the RO, even if it reads lower on the pH. Adding the baking soda increases the buffer--think this would increase the pH. Adding an acid, like vinegar or lemon juice, will burn up KH and lower pH. What is the KH and GH right now?

[travelinman1969]

ph-8.0
GH-65
KH-240

[JSchmidt]

Orion's right - adding baking soda will increase your buffer (KH) and will either raise pH or make it much hard to lower it.

You can lower pH by adding an acid, although your KH is pretty high and it would be very difficult to stably change pH by adding an acid.

Using distilled water or purchasing RO water may be a better solution if you only need something for the short term.

Jim

[travelinman1969]

Should have said earlier, it's a 150. That's a lot of water to buy. I used to do that a while back and not wanting to do that again. Walkin out of Wal-Mart with 75 gallons of water is a chore.

[pinballqueen]

would it be possible to lower it via natural means? Such as dead leaf litter, peat moss, driftwood, etc? I'm not sure how effective it would be in such large quantity, or what measures would have to be taken to do it though....

[daveedka]

Peat can be very effective if your KH isn't too high, It bleeds natural tannins and eats up your KH and lowers the ph, It's the only thing I ever used effectively without a lot of work, Driftwood will have the same effect at first when you put it in, but it basically runs out of tannins after a few water changes(as does peat) and is much harder to replace than peat in the filter. Baking soda, has the opposite effect from what you are trying to do as said above.

[JSchmidt]

With a KH of 240 ppm, you'd need a lot of acids -- whether from driftwood or any other source -- to burn up the buffer enough to lower pH. A losing proposition... more likely to produce pH bounce every time a parial water change is done. (Partials will replenish the buffer, at least partly, and pH will rise.)

You're probably better off keeping pH stable for time being.

Jim

[travelinman1969]

okay, my arowana is not happy. Tried to commit suicide tonight. Gashed his head bad. I'm starting a new thread, I had a feeling he wasn't gonna like this ph gain. He's always been in 6.8-7.0. It happened slowly, the ph going to 8.0, if your wondering. Over a 3 week period, about 10 water changes, 15 % at a time. The water here sucks.

[got_nailed]

I know it’s not my thread but I’m going for a hijack.

I’m thinking about using my 75 gallon planted for some discus. My KH is 179 and my GH is 215. I know this is not the ideal water for this type of fish.

I have well water so getting a RO unit is out it would clog up before any water would come out. I have thought of getting 100 gallons of bottled water at Sams. I have tried to find some one that would sell me water form there RO unit but no one has one that will do over 10 gallons a day and no one will go for it.

I don’t think it would be to bad after the tank is filled and the plants readjust to the new water. Fish in the tank would be moved till the tank settles out. I know I would need to add a sump and i think I would need to use some peat.

Any thoughts would be helpful.

Nailed

[travelinman1969]

Hijack it buddy, I'm starting a new one. LOL!!

[got_nailed]

It’s on the same line so why not.

[happychem]

Get a new RO unit. For the volume of water that you're talking about, I don't think that any diy action will be very effective.

I'm not sure about tannins having any effect on KH. Tannic acid should lower pH, but I'm pretty sure that the conjugate base, what's left after the H+ leaves and lowers pH, would contribute to KH. The net effect should balance, like adding CO2, pH goes down, KH stays the same.

Like OG said, water softner won't help either. It's just an ion swap. I'm not even sure that it even affects carbonates. I think that it just works on the cations Calcium and Magnesium, but I'm not positive about this.

[RTR]

happchem - for the standard salt-exchange softeners, you are right on. only Ca++/Mg++ swapped out for Na+. Acid-base resins will do both anions and cations, but the tanks have to be swapped out for recharge, not a home practice IMHO, too $$, too hazardous.

[happychem]

So, for the watersofteners that people have in their homes that use NaCl or KCl for ion exchange, do these swap Cl- for carbonate species? My learning on water softning was more off hand knowledge than study, and all I picked up on was the Na/K swap for Ca/Mg.