Alkalinity creeping up over time

[gabesreef]

So I’ve been reefing for a couple years now And my current tank is hitting the one year mark soon but it was set up with half established rock and half new. This tank has a unique problem that I haven’t had before the alkalinity is creeping up over time. For example I do a water change and test both aquarium water and tank water. Tank water 8.3 and water change water is at 8. I do my water change come back next week to do another and the alk is now at 8.6...... I’m stumped but this is creating an issue because last week the water was 8.8 I did a water change and had a mini alk drop because my water change water was at 8. So now my tank levels are sitting at 8.3 again so .5 of a drop in dKH. How is my water going up in alkalinity over time?!?!? Lol the tank is stocked with a mix of LPS and soft coral with a medium bio load of fish and a couple of nems. I mix my water 24 hours before using it. As far as filtration in the tank it’s just filter socks, skimmer and a lot of Cheato. I dose microbactor7 once a week 10mls. 75g tank with 30 gallon sump. I mix my water to 1.025 and use Red Sea blue bucket salt. 10g water change every 7-9 days. LPS in the tank is suffering because of the frequent fluctuations.

 

[gabesreef]

Anyone?

 

[wculver]

I have been having the same issue with a mixed tank myself over the past two years. I have been using Aquaforest 3 part and mix myself. I can't seem to figure out what causes the alkalinity increase but when it does the increase is quick within 2-3 days. Typically I know it's gone off before testing just by looking at the coral.

If at some point somebody has an idea I'd too love to hear what you think.

 

[Randy Holmes-Farley]

I have been having the same issue with a mixed tank myself over the past two years. I have been using Aquaforest 3 part and mix myself. I can't seem to figure out what causes the alkalinity increase but when it does the increase is quick within 2-3 days. Typically I know it's gone off before testing just by looking at the coral.

If at some point somebody has an idea I'd too love to hear what you think.

Can you clarify what you mean? You are dosing an alk supplement. Just dose less?

 

[Miller535]

Do not forget that most ph buffers will also increase alk. I am not sure what all you are using supplement wise.

 

[Tankkeepers]

Following as I have no clue and would like to know only thing I can think of is for some reason your rock or sand is breaking down causing a rise but thats a best guess

 

[Tankkeepers]

Also if your using a ph buffer it will raise alk as ph and alk are directly related you cant change ine without changing the other