need to raise ph of topup water ?

[onghm]

Hi,

Currently I'm using DI water to topup the evaporated water in main tank.

Observed that the PH of my DI water is quite low.

Do I need to raise its PH to 8.3 (using seachem liquid marine)

before adding to main tank ?

Thanks

[Tanzy]

DI water pH low? How low? Can you give a figure?

[onghm]

Hi Tanzy,

I'm using JBL PH testkit.

The color I got is quite orange

Probably 7.4 to 7.6

thanks

[BlueTerror]

Yesh, i would also like to ask, does newly mixed water reach a pH of 8.0 and above? I measured the ph of my tank after i placed LR and sand in, and it's only about 7.7?

[Tanzy]

onghm,

That sounds like normal pH for DI water. Pure water has a pH of exactly 7. There's no need to bump up the pH because you are merely replacing the water lost to evaporation, which is pure water.

Blueterror,

Newly mixed water? Do you mean freshly mixed saltwater? If it is mixed to the correct salinity it shouldn't be too far from pH 8.3, maybe +/- 0.2.

7.7 does seem a bit low. It could be due to acids produced because of decomposition during the cycling or that the tank has poor gaseous exchange and carbon dioxide is building up, depressing the pH.

[Sinn]

poor gas exchange?

could u elaborate ?

[Tanzy]

During respiration, oxygen is used and carbon dioxide is released. When carbon dioxide dissolves in water, it decreases the pH. The only place that this carbon dioxide can escape into the atmosphere is at the water surface. So if there isn't enough surface aggitation or circulation of water to the surface, carbon dioxide can't escape and will buildup.

[onghm]

Thanks Tanzy.

Hmm...so its like salinity, ie water evaporates but salt remains in tank.

Along this theory, does PH increases like salinity when a substantial amount of water evaporates ?

I'm not able to maintain my PH constantly at 8.3

It quite often drops to between 7.9 and 8.1

As I'm toppping up water daily (I got 3 DC fans to keep my temp < 27 deg),

I thought the DI water is pulling my PH down.

Was thinking of bumping its PH up before topping up.

Now I know the water is not the cause.

Thanks for getting me off the wrong track.

Have to troubleshoot elsewhere then.

[Tanzy]

It will take a lot of evaporated water to impact the pH.

pH dropping to 7.9 is a sure sign of carbon dioxide buildup. Do you have an overflow system or a skimmer? You might need to increase the water movement at the surface. Adding a pH buffer like Seachem Reef Buffer is a way to prevent pH from fluctuating too much, but the carbon dioxide still needs taking care of.

Do you measure your alkalinity?

[onghm]

No, there is neither overflow nor skimmer.

Only 2 powerhead and a surface skimmer.

A protein skimmer is on my next to-buy list.

I thought I would at least get a pass on my water movement as :-

1) u can see tiny waves/ripples crashing into each other generated by the diagonally opposite powerheads.

2) water surface when view from underneath is clear of any dust film.

3) the random water movement from powerhead were able to reach all the way to bottom of tank as I can see my coral swaying.

Now you mentioned about carbon dioxide, maybe its my topup water again.

I normally filled up 2 big bottles with DI water on weekend and then capped them up to be used for the rest of the week.

I will use airstone to aerate the bottle overnight and see if it helps.

My dkh is 8.

Is it too low ?

[Tanzy]

I won't bother with aerating the top up water. It won't make a difference. The carbon dioxide is in the tank and not in the top up water.

If you add a good skimmer, it will definitely help stabilise the pH.

dKH 8 is not low, just lower average. You might find that adding buffer to dKH 10 will help a bit.

[onghm]

ok will try to raise dkh to 10 .

I'm using seachem reef carbonate.

Skimmer wise, same constraints as all with 2ft and sumpless setup

So, I'm considering HOB redsea prizm, as quite a few people in this forum gave thumbs up for it.

thanks a lot for your time and advice.

[mv3i]

on that note tanzy .....izit normal for my PH to drop to 8 at night and back to 8.2 /8.3 in the day ....

what can i do to stable the PH at night ... running a 24/7 macroalgae in the sump .... with caulepra .... but is it really that essential ....

i have already have PS in the sump ( maybe not sufficient ... )

any recommendations

[Tanzy]

mv3i,

Sounds normal for the pH to fluctuate between day and night but 8.0 is a bit low. Make sure it doesn't go below that.

The macroalgae refugium is already helping to stabilise the pH.

How about a bigger skimmer? Maybe you can increase the turnover of the tank and sump or get some more water movement in the tank itself. Alternatively, you could leave it and don't worry too much if the inhabitants are unaffected.

[mv3i]

was thinking about that ... H&S counds good ???

but too x leh ... or DIY beckett PS but dunno where to get all he parts and 1048 is out of stock in singapore ... can get overseas ??? can help ??

i'm sure my turn over is quite good ...

ehiem 1060

and

hailea 6540

[Tanzy]

You can get the Beckett injector from My Reef Creations. It might not be available on their website, but they will get one for you if you email them. It's US$18 for one, not including postage. It costs US$20 to mail to UK.

[mv3i]

is it available in australia ??