Question about water changes

phishman1 · 01/16/2021, 09:47 AM

I have a 46 gallon, having issues with higher alkalinity, was 20 now 12, down to 12 in like 4 days. However, calcium is low, way too low, again today at 260. I have added calcium from the LFS, 2 and half caps, over 3 days, still 260. 20 percent water change today, the water going in from the store tested at 440.

Question is: In my tank how long should I wait to retest to see where I am parameter wise.

The tank seems fine, everything growing well, fish fine, corals fine, inverts ok, so realizing the Alkalinity needs to come down and the Calcium need to go up, I'm on it.

billdogg · 01/16/2021, 10:26 AM

I would check your magnesium level as well. If it is out of whack (especially if it's low) it's nearly impossible to keep Ca and Alk where you want them.

Uncle99 · 01/16/2021, 03:20 PM

Check to make sure MG is in the 1260-1360ppm range and salinity is 1.026.
You can increase .5dkh per day safety.
Increase both Alk and CA together. Keep track of how much dosed and effect on water.
It takes a bit of work to get them in the bands.
Then you need to test every 24 hours for say 4 days and divide the total decrease of Alk by the number of days to get a estimate of your consumption.
Once you know consumption, then keeping it there is easy, check weekly.
If I am dosing say 30ml Alk solution then I dose 30ml of CA.

I have some concern of those Alk changes because everything looks good, a wild swing like that should have created much unhappiness.

Any chance the test is not accurate.

If your looking for accuracy and speed, use Hanna Alk Checker for this important parameter.

01/16/2021, 09:47 AM	#1
phishman1 Registered Member Join Date: Jun 2002 Location: Daytona Posts: 62	Question about water changes I have a 46 gallon, having issues with higher alkalinity, was 20 now 12, down to 12 in like 4 days. However, calcium is low, way too low, again today at 260. I have added calcium from the LFS, 2 and half caps, over 3 days, still 260. 20 percent water change today, the water going in from the store tested at 440. Question is: In my tank how long should I wait to retest to see where I am parameter wise. The tank seems fine, everything growing well, fish fine, corals fine, inverts ok, so realizing the Alkalinity needs to come down and the Calcium need to go up, I'm on it.

01/16/2021, 10:26 AM	#2
billdogg Registered Member Join Date: Apr 2008 Location: Grove City, Ohio Posts: 10,806	I would check your magnesium level as well. If it is out of whack (especially if it's low) it's nearly impossible to keep Ca and Alk where you want them. __________________ I'll try to be nice if you try to be smarter! I can't help that I grow older, but you can't make me grow up! Current Tank Info: 120 mixed reef with 40b sump, RO 150 skimmer, AI Sol Blue x 2, and a 60g Frag Tank with 100g rubbermaid sump. 2 x Kessil A360w lights, BM curve 5 skimmer

01/16/2021, 03:20 PM	#3
Uncle99 Crab Free Zone Join Date: Sep 2017 Location: Ontario, Canada Posts: 2,906	Check to make sure MG is in the 1260-1360ppm range and salinity is 1.026. You can increase .5dkh per day safety. Increase both Alk and CA together. Keep track of how much dosed and effect on water. It takes a bit of work to get them in the bands. Then you need to test every 24 hours for say 4 days and divide the total decrease of Alk by the number of days to get a estimate of your consumption. Once you know consumption, then keeping it there is easy, check weekly. If I am dosing say 30ml Alk solution then I dose 30ml of CA. I have some concern of those Alk changes because everything looks good, a wild swing like that should have created much unhappiness. Any chance the test is not accurate. If your looking for accuracy and speed, use Hanna Alk Checker for this important parameter.