Ph Goes Up Over 9 And Falls Then Down To 8.0

[dilbert]

Hi all!

I got only a brackish tank. It's 60 Liters (15 gallons). When I had set it up I added the salt directly to the tank as there was only some Java ferns and some gravel in there.

I used ULTRAMARINE Synthetica sea salt and i added 600 g of salt to make SG 1.005 brackish water.

My tap water is 7.25 ph, KH 3.3° (60 ppm), GH 6.7° (120 ppm).

Half an hour after pourring the salt into the water, I measured a ph of 9.4.

The next day is was ph 8.0 and kept at this figure. KH is in the tank 6.7° (120 ppm) and GH 10° (180) as stable as those test strips are telling. I added also Aqua Plus water conditioner but I read now that this specific sea salt has its water conditioner already in itself.

Yesterday evening, I prepared only a small glass and it was again ph 9.4 and two hours later still ph 9.15. I used my newly bought ph-meter (+_ 0.02) for that and doublechecked it with a ph drop test.

Does this mean I need always to prepare the water one day in advance when I'll have fish and shrimps in there as they presumably don't enjoy much of that ph spike.

I found some hints in here

Buyer's guide to marine salt

But there it says that other salt would go over ph 9, but the salt I am using only to ph 8.6. Can someone shed some light on this as I am somewhat confused, now.

 

[AK77]

Hmm that's a bit of a pickle.

Mixing water up in advance and leaving it to mix for at least 24 hours should help it stabilize. I know you are only making brackish water but this may very well explain the fluctuations you are experiencing. When mixing RO water with salt, I age the water for a couple of days and aerate it to drive out CO2 and oxygenate the water.

If you are using a calcium carbonate based substrate, this will act as a PH buffer too, so may be keeping your PH somewhat higher than you want. I don't have any experience or knowledge of Brackish tanks so can only suggest things that affect PH in marine ones.

 

[SkiFletch]

Yeah, couple quick tidbits on pH. Newly mixed saltwater, or even brackish water will experience big pH swings. The water should be mixed in a tank/bucket with a powerhead to agitate and stir it. The more water movement, the better. Then once in your tank, if the tank water is fully stagnant, you'll still see pH swings there due to CO2 buildup and offgassing. Bottom line, flowrate will help level things out

 

[1entra]

Sorry to be hijacking your thread dilbert but I also seem to be having a problem with maintaining a consistant pH in my nano reef. The tank has just finished cycling and the pH keeps moving going up and down. It is currently at 7.8, which I believe is too low for a marine reef as pH should ideally be approx 8.3 correct??!

Well I am not currently using any buffering agents, just seachems reef salt and i have an aragnite/coral sand mix subtrate (which I have been led to believe should help with buffering the pH?).

No the question is should I use a reef buffer before adding any lifestock to get the pH up to 8.3 or should I leave the tank be without adding any chemicals?

 

[SkiFletch]

Low pH is OK so long as it's stable pH. Test just before lights on and just before lights out and see if there's a pH swing before you consider additives. Also, low pH is very common in freshly cycled tanks.

 

[1entra]

So would it stress/damage my livestock if in the future I decided the pH was too low and so needed bufferingwith the aid of additives?

 

[SkiFletch]

You can use additives for sure. Just make sure you know what you're using, how much you're using, and how to test for it. I'd suggest reading through some of the chemistry links I posted in the "realm of knowledge" thread atop the marine chit-chat section (page 2)

 

[1entra]

Cheers skifletch but how would i be able 2 raise pH without causing stress to the livestock?

PS. I cant seem 2 find the links to your "reams of knowledge", any chance you can post the link here please

 

[1entra]

Never mind, found it. cheerz

 

[dilbert]

Just an update to that.

I bought from another dealer sea salt in a small plastic bag. He sells it that way or you have to buy a 25 kg bag. I forgot the brand name he mentioned, but this salt at first dissolves way much faster and better. It almost dissolves on its own.

And the ph of this soup is not 9.4 anymore but 8.0 instead with my tap water having 7.3.

I just measured the salinity to be sure not having bought some other white stuff and it has the same salinity with the same weight of salt into the same amount of water.

That's amazing.

 

[SkiFletch]

Yup, that sounds a little more like it. Prolly a bad batch of salt originally