High alkalinity level

[paultaylor]

Hi guys,

I have a very high alkalinity level.

All the other tests seem fine :

pH = 8.2
Alk = V high on test, 14 dKH on another
Nitrate = 0
Nitrite = 0
Calcium = 420
Magnesium = 1360

I read somewhere that if the calcium level drops too far then this in turn can cause the Alk level to sharply rise, is this true ? It was at about 360 yesterday when I added the Calcium supplement but today the Alk is still high.

I can’t seem find any details on lowering the Alkalinity level, increasing it yes but not decreasing it. I think the Alk has been high for a while, a test kit I had was not giving me good results.

The tank is doing fine, the corals seem fine, no algae growth. I did notice the fish a little stressed today, not that its linked maybe.

Thanks in advance for any replies,
Paul

 

[Anonymous]

I read somewhere that if the calcium level drops too far then this in turn can cause the Alk level to sharply rise, is this true ?

No, that's not true. The only way to raise ALK is to add a buffer agent like Carbonate or Borate. If you stop adding it then ALK will slowly drop. Just continue to maintain your Calcium where it is and stop whatever you're adding to raise the ALK until ALK drops back down to where you want it.

It's also a good idea to occationally test your makeup water to be sure it's not causing an unbalance.

 

[paultaylor]

Just continue to maintain your Calcium where it is and stop whatever you're adding to raise the ALK until ALK drops back down to where you want it.

The only supplements that I add to my tank are Calcium, and Magnesium occasionaly.

Does this mean that my supplements are to blame by raising the Alk too high whilst supplementing the Calcium ?

Paul

 

[Anonymous]

Interesting.

Have you tested your makup water for ALK? It's coming from somewhere.

Do you have any cement in the tank? I know that sounds strange but it has happened...

 

[paultaylor]

No, no cement in the tank.

I'm in the process of creating a new 20% water change. The salinity is about right and temp ok. I tested it straight from the prep tank and I get the same result, very high alkalinity.

I then tried to test the RO water before the salt goes in. The test didn't work, ie so low off the scale, I'm therefore assuming that the test only works with salt water.

Is it my RO unit causing it, maybe. I think I'll get some fresh water Alk tests and check the water before the RO unit and then after before adding the salt to see what happens.

I'll also hang fire on the water change until I get this under control.

Thanks for your help, I'll let you know what results I get.

 

[Anonymous]

Sure sounds to me like it's the salt mix.

 

[ChrisRD]

I second what Guy said. If your alk really is that high with freshly mixed saltwater then it sounds like your salt mix is the problem. However, I would double check with another test kit (I like Salifert kits) or have your LFS test your water to make sure you actually have high alk before coming to any conclusions.

 

[tmc]

instant ocean has been know to have a high alk around 12dkh. i had to switch salts to get mine down.
tmc