Why are my Ca levels stuck at around 400?

[DNA]

These are the measurements for 2013

Date.......pH..°C..Ca..Alk..Mg..Nitrat
05.01.13 8,08 27 400 7,7 1200
12.01.13 7,98 27 400 7
19.01.13 8,00 27 375 7,7
26.01.13 7,93 27 365 7,7
02.02.13 7,95 26 400 9*
10.02.13 7,95 26 400 7,7 1125 0
17.02.13 7,98 26 435 7,7 1200
23.02.13 8,03 26 390 9,6 1120
02.03.13 8,02 27 405 9,6 1200 0
09.03.13 7,97 26 400 9,3 1275
16.03.13 7,97 26 390 9,3 1275

On the 17.02.13 I switched to salifert Mg test kit and added Mg rocks in the Ca reactor.
A few months ago I manage to raise Ca levels by around 20 by replacing a Salifert test kit by another identical one.
The Ca levels before that used to be at around 380

My calcium reactor is a Deltec pf 601 and it is Suitable for Aquariums:.....
Heavy Stocking and High Illumination - 1350 lts - 300 imp. gallons - 356 US gallons*
Normal Stocking and Illumination - 2000 lts - 444 imp. gallons - 528 US gallons*
My tank is between light and normal stocking 320g.

This is the calcium reactors effluent.
Ca...Alk..pH...Flow
600 35 6,23 .7 ml/sek

I've got dry rocks in there so it's filled to the top with it.
The flow through it is already above what is recommended and so is the CO2.

My initial thoughts was that coraline algae forming on the dry rocks in the tank would suck huge amounts of Calcium from the water.
It's already been a year and I don't have much coraline.
My acroporas are doing good but birds nest and pocillioporas are not.

I did try to add 8g of kalkwasser over 3 days from 23.02.13 to raise pH and Ca, but pH stayed the same, Ca came out at 390 after and alk raised from 7,7 to 9,6.

So what do you recommend?

[TylerHaworth]

Your Mg is not high enough to hold higher calcium levels, although it appears to be headed in the right direction. Dose it up to about 1350 and then try to manually dose Calcium up to the level you desire.

[jerpa]

You will have to manually dose just a calcium supplement to have a large effect on calcium without your alk sky-rocketing. Calcium reactors and kalkwasser are balanced additives. They add a very small amount of calcium relative to alkalinity.

I disagree that your magnesium level is too low to support those calcium levels. I've never had a problem keeping calcium over 420 even when magnesium fell into the 1100's. I also doubt that your calcium levels are an issue. They are well within the normal ranges and stability in regards to alkalinity is more important IMO, especially for SPS. My birdsnests and pocillopora seem to be the most easily killed by alk swings. I always heard acropora were more sensitive but my experience has been the total opposite.

[DNA]

Thanks for your comments.

Anyone else care to share their thoughts?

[coralsnaked]

Originally Posted by jerpa

You will have to manually dose just a calcium supplement to have a large effect on calcium without your alk sky-rocketing. Calcium reactors and kalkwasser are balanced additives. They add a very small amount of calcium relative to alkalinity.

I disagree that your magnesium level is too low to support those calcium levels. I've never had a problem keeping calcium over 420 even when magnesium fell into the 1100's. I also doubt that your calcium levels are an issue. They are well within the normal ranges and stability in regards to alkalinity is more important IMO, especially for SPS. My birdsnests and pocillopora seem to be the most easily killed by alk swings. I always heard acropora were more sensitive but my experience has been the total opposite.

+1 on the ca suppliment to manually raise the ca w/o affecting the Alk.
-1 on the Mg levels 1100's is too low and although it should not cause Ca to precip it never hurts to keep it within params. Better too high on Mg than too low. Too low may also facilitate alage growth to take hold.
+1 on the Alk swings being more problamatic on any SPS corals. The birds nest is more prone to STN where the Acros are more prone to RTN and therefore wide Alk swings can have a more dranatic affect in short periods of time. One day nice next day not so much.

[bertoni]

Magnesium at 1100 ppm is a bit low, but should be fine, in my experience. I ran tanks for years at 1100 ppm because that's what IO measured. I'd probably raise it to 1270 ppm or so, the canonical ocean average, out of general caution.

Those numbers all seem acceptable to me. Are any animals having any trouble? You can add some calcium chloride if you want to raise the calcium level, but I wouldn't bother, personally.

[saltyair]

Raise your PH to 8.03 0r 8.04

what type of salt are you using?

[bertoni]

The pH levels for the tank are fine as is, IMO. Lots of tanks run in that range.

[Trevenator]

Originally Posted by TylerHaworth

Your Mg is not high enough to hold higher calcium levels, although it appears to be headed in the right direction. Dose it up to about 1350 and then try to manually dose Calcium up to the level you desire.

+1

I could not get my calcium over 400 for 6 months no mater what I did.
Then just raised my magnesium to 1350 and boom have had no problems since holding it stable at 450.

[DNA]

After having kept the calcium reactor in overdrive for weeks and topping the tank off with kalwasser I'm pretty sure the test kit is playing tricks on me.
Calcium is at 330 and alkalinity at 10. That does not make sense.

This would be my third and most severe issue with test kits.
I'll verify this next week when I get another test kit.

[hypnoj]

It's also my experience that kalkwasser and Ca reactors don't work well for raising calc, only maintaining it. You'll have to dose Ca to get it higher. I purposely run my Mg at around 1400 in order to keep my Ca around 450.

[DNA]

That's the plan. I finally found a company today that sells CaCl to the public.
It sure is expensive, $100 for ~10pounds. (5 kilos).

[kuyatwo]

Originally Posted by DNA

That's the plan. I finally found a company today that sells CaCl to the public.
It sure is expensive, $100 for ~10pounds. (5 kilos).

Cacl you can find at any pool supply store.


Sent from my iPhone using Tapatalk

[DNA]

This is Iceland, I don't think we have a pool supply store.
We have big public pools and they buy wholesale somewhere.

The stuff I'm getting is food grade. I though that was important.
There are unwanted trace elements in CaCl.

[bertoni]

Food grade might be fine. I'd just watch the tank carefully for a while. Does it come with a list of ingredients?

[DNA]

This is it.

http://www.applichem.com/en/shop/pro...ttelqualitaet/

The plan was to go very slowly on the dosing.
If you got any good advice it would be appreciated.

[Habib]

You can make a say 25-50% solution (caution it can get hot when preparing it).

Add that in a high flow area. You can easily raise calcium by 20 ppm a day.

[David Grigor]

First off, there is nothing wrong with a 400ppm Calcium level. There is no need or advantage to have it higher. Corals aren't going to grow any faster with higher levels. Just so long as it never reaches levels to inhibit calcification ( 360ppm ) your fine.

[bertoni]

I agree that 400 ppm is fine. That product seems like a reasonable choice to try, although it's hard to guarantee that it'll be okay.

[DNA]

Finally I got another Salifert calcium test kit.
I made two tests with the old one and two with the new.

The old gave me two readings at 300
The new gave me two readings at 340

Alkalinity is at 9,3
Magnesium is at 1080

My experience with these test kits is that there will be a drop as they get older.
A comparison of my last three test kits and between two at a time reavealed a difference of 40 today and 20 last year.

This means my calcium levels may have been at around 440 when I wrote the initial post in this thread.

-------

Starting to add CaCl now to raise Calcium levels.
Anyone care to make an estimate how much will be needed?

[hypnoj]

I wouldn't do a single thing until I raised my Mg above 1350.

[DNA]

I already added 6.2 ounces (175g) to my 420g (1600 liter) system.
That raised the calcium levels from 340 to 365.

-----

I agree that Mg level should be higher.
There have been Magnesium rocks in the Ca reactor for 2 months now.
It seems like I need to add more of them.

I also have some Magnesium Sulfate lying around, but I don't like it much since a lot is needed to raise Mg levels.

[hypnoj]

I agree that it requires a lot of mg to raise levels. I think Kent Tech M mag is the most potent on the market; making your own from Epson salt is the cheapest and easiest though (but a lot has to be added). Just adding more mag rocks to your Ca reactor won't necessarily help you more. Mag rocks require a lot lower pH to work so dosing Mg will still probably be required.

[bertoni]

1080 ppm is a bit low, but not that bad. I'd raise it to 1275 ppm or so, but I'm the cautious sort.

This calculator will help with doses:

http://reef.diesyst.com/chemcalc/chemcalc.html

You'll need to guess at the actual water volume in the system, so it might take a few tries to get an accurate dose. I'd target 50 ppm at a time for calcium and magnesium.

[OnTheReef]

Originally Posted by hypnoj

I agree that it requires a lot of mg to raise levels. I think Kent Tech M mag is the most potent on the market; making your own from Epson salt is the cheapest and easiest though (but a lot has to be added). Just adding more mag rocks to your Ca reactor won't necessarily help you more. Mag rocks require a lot lower pH to work so dosing Mg will still probably be required.

This is my experience as well; I simply could not get my Ca above 360-380 ppm until I started monitoring and raising Alkalinity and Magnesium. Kent Tech M Magnesium is an excellent product.