KH problem..

[wa_lanz]

after a water change last week, got my dKH to 8..

4 days ago it was at 7 and i just measured it just now and was surprised to have a reading of 5.4!!! test 1 more time its still at 5.4dKH!!

CR working perfectly, tested the effluent and had a reading of 64dKH..

calcium reading of 400ppm from tank... corals having new growth but some bases STNing..

anyone care to enlighten me on why my dKH is getting lower and lower??

[zarkon]

Not that I'm an expert .. May guess it's ions imbalance. Was it balance in day one?

[weileong]

Did you check your Mg levels?

[AlfaRomeo]

Whats your MG levels?

Anyway, it might be that the CR effulent is 64dKH but the supply is not meeting the demand in your SPS dominated tank. Try increasing the flowrate of the CR and maintaining the 64dKH from the effluent from incresing the bubble count too. That will deliver more dkh/CA to your tank and meet the demand better.

hope that helps

[wa_lanz]

all other parameters in check.. only prob is with dKH reading.. and will increase my effluent drip rate now.. and see how... hopefully wont cause stn....

thanks guys..

[madmac]

wa_lanz you have a beautiful tank. My compliments to you.

Increasing your effluent drip wont help as it increases in a balanced way... both Ca and dkh will go up... together.

You'll need to jus bump up your dkh readings independently of the others.

Your SB cud be the culprit, .... taking up excessive base to neutralize acids. You'll need to figure out the why STN on the base... it could be an excessive dkh swing or your rocks are too nutrient loaded, causing your SPS to wick up PO4... if that is the case, you'll see a green tint at the base.

I don't think it due to excessive dkh swing as base on your givens, you are losing 0.4 dkh a day.. which is not excessive...

best to u.

[AlfaRomeo]

wa_lanz you have a beautiful tank. My compliments to you.

Increasing your effluent drip wont help as it increases in a balanced way... both Ca and dkh will go up... together.

You'll need to jus bump up your dkh readings independently of the others.

Your SB cud be the culprit, .... taking up excessive base to neutralize acids. You'll need to figure out the why STN on the base... it could be an excessive dkh swing or your rocks are too nutrient loaded, causing your SPS to wick up PO4... if that is the case, you'll see a green tint at the base.

I don't think it due to excessive dkh swing as base on your givens, you are losing 0.4 dkh a day.. which is not excessive...

best to u.

Both will go up in a balanced way. CA of 400 is not high so it can go up without issues. Also, CA will not go up very high but you will see a vast improvement in the stability of KH.

Objective of a CR is to hold/maintain the parameters (if properly tuned). So best way is to raise the dkh manually and at the same time incresing effluent flowrate and monitor if the dkh stays steady with the new flowrate/bubblerate.

[FuEl]

Yep agree with you madmac. Carbonate hardness (kH) often depletes faster compared to Ca levels due to neutralization by acids such as carbonic acid. You might want to consider kalkwasser drips or maybe even a kalk reactor such that the hydroxide ions can neutralize the acids in place of carbonate ions.

[weileong]

A CR supplies the kH and Ca in a balanced ratio. However in NSW the ratio of kH and Ca is 1:20.

In the case when the CR could not supply sufficient kH and Ca to meet demans then kH will always seem to be dropping faster than Ca (or if not so worst case sometimes kH seems to drop but Ca remains stable).

If your Mg levels are in good order then I suggest like what Alfa has said, increase the effluent flow of your CR and then increase CO2 bubbling to keep the same dkh from the effluent.

At this moment I guess adding in of supplements is not necessary as that might affect the ionic imbalance.

[Reefaholic]

Best is to get a pH controller to maintain your CR. so no problem after setting up no matter what your bubble count is.

[Eric]

after a water change last week, got my dKH to 8..

4 days ago it was at 7 and i just measured it just now and was surprised to have a reading of 5.4!!! test 1 more time its still at 5.4dKH!!

CR working perfectly, tested the effluent and had a reading of 64dKH..

calcium reading of 400ppm from tank... corals having new growth but some bases STNing..

anyone care to enlighten me on why my dKH is getting lower and lower??

Kalkwasser dripping shld helps.

[wa_lanz]

thanks guys... learned a lot of new info... will do wat i can and hope the stning will stop...

reefing always have so many probs.. neverending 1...

wonder when can i just sit back and enjoy the new growth and colours instead of being a slave to the tank ....

and ya, thanks for the compliments madmac..