Alk Consumption

[BigKid4788]

I'm looking for a little help as I cannot seem to figure out what is going on with my tank.
Tank (350 gallon total) has been set up and running for little over a year (rock came from tank running for 4 yrs). I noticed my ALK continuing to climb even though I didn't adjust the dosing amount (currently doing Triton). I turned off the dosers for a week and my Alk only went from 9.6 to 8.7 (salifert). I have noticed that my SPS aren't growing very fast. I haven't really changed anything that would make me think the change has negatively effected them. Parameters are below (performed by Salifert Test Kit)
Alk (see above)
CA- 450
Mg-1410
Nitrates- (5-10)

Run (5) Radion G4 Pros (AB+ @ 67%, overall only 48%)
I'm getting ready to send a sample to Triton to see if there is anything in the water. I was also planning on doing a water change to see if that would help. Any thoughts or suggestions are welcome.

Thanks,
Bigkid4788

 

[pluikens]

Are you dosing Core7? How many ml were you dosing each day? I would have suggested lowering the dosage to below daily consumption so that the alkalinity dropped slower. What dKH are you trying to get to? If you still plan to go lower, I would turn the dosers back on but dose less than consumed daily.

 

[glb]

The Alk not dropping makes sense if your corals aren’t growing. Is the Ca depleting at all? Is anything else off (PO4, temp, SG)?

 

[BigKid4788]

The Alk not dropping makes sense if your corals aren’t growing. Is the Ca depleting at all? Is anything else off (PO4, temp, SG)?

Calcium is steady as well. Temp fluctuations are 78-80 throughout the day. Sg is steady as I ha e an ATO. I’m stumped to why the hault in growth and usage

 

[BigKid4788]

Are you dosing Core7? How many ml were you dosing each day? I would have suggested lowering the dosage to below daily consumption so that the alkalinity dropped slower. What dKH are you trying to get to? If you still plan to go lower, I would turn the dosers back on but dose less than consumed daily.

I am dozing core 7. I was steady at 8 but then slowly raised as consumption lowered. I’m trying to figure out why the slow down if changes ha e been minimal. Appreciate the feedback

 

[pluikens]

What was your daily average pH back when alk/calc consumption was greater and what is it now?

 

[BigKid4788]

What was your daily average pH back when alk/calc consumption was greater and what is it now?

My ph was higher as I kept my windows open. They have been closed for the last few months as it’s gotten hotter.
My ph was 7.9-8.2, now it’s 7.8 - 8.05

 

[pluikens]

I feel like the decrease in consumption could be pH related. You said that over a week with no dosing, the alk dropped from 9.6 to 8.7 so 0.129 dKH is the daily consumption. Do you know what your daily consumption was a few months ago when your pH was higher? My daily dKH demand is 0.2 when my average daily pH is right around 7.95. Back in the spring when I had my windows open and average daily pH was 8.15 or so, daily dKH demand went up to 0.5.

 

[jda]

If all of your parameters are stable, then it is your lights. Most SPS folks end up with T5s along with their Radions for exactly these reasons. If the parameters are not all that stable, then start there first.

I have had fantastic acropora tanks with PH from 7.78 to 8.02 in a closed up home. There is some indication that calcification is slowed a bit, but even with a slight slowdown, you should be seeing good growth still. IMO, the difference between these two is very good compared to outstanding.

You might get more help in the SPS forum.

 

[pluikens]

If all of your parameters are stable, then it is your lights. Most SPS folks end up with T5s along with their Radions for exactly these reasons. If the parameters are not all that stable, then start there first.

I have had fantastic acropora tanks with PH from 7.78 to 8.02 in a closed up home. There is some indication that calcification is slowed a bit, but even with a slight slowdown, you should be seeing good growth still. IMO, the difference between these two is very good compared to outstanding.

You might get more help in the SPS forum.

To be clear, I was not staying that growth could not be achieved in a tank with pH of 7.8 - 8.05, but a drop in pH could be an explanation for decreased alkalinity consumption. I believe the terms "good growth" and the OP's "growing very fast" are quite subjective so I was only trying to find an explanation for the decrease in dKH demand.

The OP did not mention changing the lights or schedule so what are you suggesting by stating it's the lights? Do you suspect shading has become an issue which is causing a decrease in growth?

 

[BigKid4788]

If all of your parameters are stable, then it is your lights. Most SPS folks end up with T5s along with their Radions for exactly these reasons. If the parameters are not all that stable, then start there first.

I have had fantastic acropora tanks with PH from 7.78 to 8.02 in a closed up home. There is some indication that calcification is slowed a bit, but even with a slight slowdown, you should be seeing good growth still. IMO, the difference between these two is very good compared to outstanding.

You might get more help in the SPS forum.

I forgot to mention I do have (4) 5’ T5’s as well as my radions.

 

[SEMA]

As PH average goes down, average calcium/alkalinity consumption goes down.

 

[jda]

In my experience, what is happening is a slowdown in Coralline algae growth and not so much in SPS or even LPS. I never noticed a difference in my clams, either, but I did not pay super-close attention. There are a lot of reasons that carbonate and calcium consumption can go down.

I had chronically low PH tanks in the midwest where the air was bad (too hot or full of pollen and allergens) and our house was constantly closed up with only a few weeks of reprieve in the fall. Now that I am in Colorado, we have windows open 325 days a year and my PH is ideal. I am within 10% now that I was in Missouri with the tight-house-pollen-air.