[Quentin]

My tap water comes out around 8. Which I've grown to live with but then I decided I wanted to keep some CRS. The CRS lasted about two months, then either jumped out or went MIA. Anyways, after a few months later I decided I want to add CRS again (they'll be here this week). This time I want my water perferct.

Ammonia, nitrates, nirites are all good. PH is still high. I realized the filter water I get from a Brita filter lowers the PH to 6. So I figured if I put 6ph water into my 8ph tank it should level out around 7? Seems logical, however I have done two 50% water changes and it still wont come down. I got excited last night b/c the water was around 7.2, but 24hrs later it's back near 8.

Any help/advice? I rather not use peat. I dont get how low ph water wont lower the overall ph. Thank has 3 pices of pacific ocean driftwood, some blxya, and some dwarf sag. Substrate is a sand type mixture.

My job has RO water however even that has high ph:icon_conf

 

[2in10]

Your water at home most likely has a high alkaline level (KH). You will either want to use RODI water and then hard minerals back in to get your pH stable or use a non phosphate based acid buffer like Seachem's Acid Buffer to lower the pH.

The pH that comes out of taps and filters will balance to what ever level the buffers in the water will be stable at.

 

[VeeSe]

Also, pH is not a linear measure; it is measured as the logarithm of the concentration of H+ ions in your water. This means that mixing pH 8 water with pH 6 water won't lower your pH to 7, even if you had no buffers in your water. Trying to average things doesn't work the same way when you aren't working on a linear scale.

 

[Quentin]

Hmmm, more complicated than I thought. I'll try to find some of that Seachem's acid buffer. Seems like the easiest way.

 

[RoyalFizbin]

Your substrate might have some buffering qualities to it. I'd take some of that substrate out and mix it with that 6ph water and test after 24hours.

 

[Quentin]

@royal I'll look into that.
@2in10 are there any other kinds of buffers, trying to find something I can find at LFS. The Seachem's I would have to order off Amazon.

 

[jasonpatterson]

If you want to keep a species that requires more acidic water, you probably ought to get that sorted out before buying that species. Call me crazy...

In any case, if your pH from the Brita filter is actually 6, then filter a whole bunch of your water through a Brita filter, let it sit for a day in a bucket and test the pH again. If it's still low, do a couple of huge water changes using that filtered water. If it comes back up after that, then there is something in the tank (coral sand substrate, a concrete decoration, who knows?) that is causing the pH to rise. You've got water that is probably buffered by carbonates to its current pH (there are other possibilities for why it would be that high but this is far far more likely) and adding other chemicals to try to get it to a desired new pH is going to have to be done after every single water change from now until forever. It's also hard telling how much of the buffer you'll have to add, as they are far better suited to adjusting relatively neutral and unbuffered systems to a particular value. In the long run you might do better investing in a reverse osmosis filter.

 

[2in10]

@royal I'll look into that.
@2in10 are there any other kinds of buffers, trying to find something I can find at LFS. The Seachem's I would have to order off Amazon.

Seachem is the only one I know of that is not phosphate based.

 

[Quentin]

If you want to keep a species that requires more acidic water, you probably ought to get that sorted out before buying that species. Call me crazy...

Yea I didn't do all my due diligence. I use to belive I could fix this with Ph Down.

 

[malaybiswas]

How big is your tank? If you are doing low tech shrimp only tank you can plan for monthly wc instead of weekly and keep some distilled water handy to do weekly top offs. Then monthly, do WC. During water change keep the tapwater in a bucket and dip some peat moss (in a cheese cloth) over night to get it acidic. After WC run filter with carbon for a day or 2 to clean up the peat coloration.

 

[Quentin]

^Good idea. Only a 4 gallon Finnex. I'm also thinking about just buying DI water. Can't be that much.