High KH in LPS Reef Tank

[REEF_TO_KEEP]

A friend of mine started a LPS reef tank 4 months ago (live rock and sand based). He is struggling with high KH measured between 10-12 KH. He could not get KH any lower than 10. High KH is stressing out the corals. He tried to prolong water as long as he could because it would bring KH back up to 11 to 12. He has been using low KH standard salt from Instant Ocean and Red Sea. Both salts indicate KH of 8 but the actual measurement of the fresh mix is between 11-12. He has quite a bit of coral but all LPS.

My though is corals would consume a lot of it.

Has anyone experienced with this issue? Can you please propose a lower KH salt.

How to bring the KH down to 8?

 

[TokenReefer]

He has been using low KH standard salt from Instant Ocean and Red Sea. Both salts indicate KH of 8 but the actual measurement of the fresh mix is between 11-12.

This is normal for IO; it's DKH is not 8, not sure where you read that. I use IO purple and it mixes at approx 11 dkh at 35ppt

 

[REEF_TO_KEEP]

This is normal for IO; it's DKH is not 8, not sure where you read that. I use IO purple and it mixes at approx 11 dkh at 35ppt

you are right. He used IO and switched to Red Sea Salt (blue bin, not the pro). Rea Sea salt has a measurement reading of KH of 11 to 12 even though it said 8.

 

[TokenReefer]

well that's a whole other scenario then

Does he dose anything that would alter alkalinity?

 

[TokenReefer]

Is he combining the salt mixes? From your post I can't tell if he switched from IO to RS or is using both...

 

[REEF_TO_KEEP]

well that's a whole other scenario then

Does he dose anything that would alter alkalinity?

he only doses Calcium and Magnesium separately. NO Kh in the calcium at all, it is Aquaforest Ca Plus. t is very puzzling to me how the KH is always high.

Could rock and sand release KH?

 

[TokenReefer]

I don't think it'd be anything noticeable/testable. There may be some chemistry at play if no buffers are being added that's beyond my pay grade. If you can get actual numbers that might help some with the riddle; esp when chemistry is involved.

 

[REEF_TO_KEEP]

I don't think it'd be anything noticeable/testable. There may be some chemistry at play if no buffers are being added that's beyond my pay grade. If you can get actual numbers that might help some with the riddle; esp when chemistry is involved.

got the numbers from him

KH - 11
CA - 425
MG- 1450
PH - 8 to 8.3

 

[TokenReefer]

Nothing jumps out at my untrained eye

So no more IO is being used right; can disregard this bit? It's just the Red Sea w 8 dkh?

Maybe there's something in those supplements? What exactly (brand/mix/compound) is it?

How's he maintaining that ph?

 

[TokenReefer]

I see you mentioned Af CA Plus. Site says it's calcium chloride which can raise alk unless I'm mistaken

He can stop adding ca for a bit as there's some wiggle room I think and let the alk drop naturally. Then dose the ca supplement again and see if it rises