Two Part Dosing Question

[hawkinsrgk]

For the last couple of months my tank has been using a lot more ALK than CAL. Wanted to get some opinions on why that would be or if this is common. Using BRS 2 part.

Dosing Schedule with dosing pump

Cal - 135 m/l per day
Alk - 200 m/l per day
Mag - 30 m/l per day

Potassium whenever it goes below 400 ppm (which is not very often and done manually)

Parameters

Salinity - 1.027
Cal - 460 ppm
Alk - 7.7 dkh
Mag - 1400
Nitrite - 0
Nitrate - 0
Phosphate - 0
PH - 8.4 - 8.52 depending on time of day
temp - 77.8 during cold months
Potassium - 456 ppm
Iodine - .09
Iron - 0

Thanks
Randy

 

[Randy Holmes-Farley Verified Community Expert]

I doubt that the tank is using much more alkalinity than the balanced amount of calcium, but many salt mixes contain high levels of calcium, so they start high and water changes keep pushing it high.

If you really do need a lot more alk additive than calcium, the recipe is probably off for some reason.

What exactly are you using?

 

[hawkinsrgk]

For ALK - I am using 2 cups of Bulk Reef Supply Soda Ash (Sodium Carbonate) per 1 gallon of RO/DI water
For Cal - I am using 2 1/2 cups of Bulk Reef Supply Calcium Chloride per 1 gallon of RO/DI water

Total water volume is somewhere between 380 and 400 gallons.
I use Reef Crystals salt and do a 35 - 40 gallon water change every week.

 

[Randy Holmes-Farley Verified Community Expert]

Do you do water changes, and if so, with what salt?

 

[hawkinsrgk]

Total water volume is somewhere between 380 and 400 gallons.

I use Reef Crystals salt and do a 35 - 40 gallon water change every week.

 

[Randy Holmes-Farley Verified Community Expert]

Reef Crystals at a sg of 1.027 will likely be adding to the calcium with each water change. A water change will add alkalinity too, but probably not proportionally as much as it adds calcium. That may be why you detect a need for more of the alk additive to maintain those levels.

My guess is that if you just used equal parts dosing with a dose to maintain alkalinity, calcium would stabilize at a somewhat higher level than you have now, closer to what the Reef Crystals contains.

 

[hawkinsrgk]

Ok. Thank you Randy for your help with all of our questions.

 

[Randy Holmes-Farley Verified Community Expert]

You're welcome.

Happy Reefing.

 

[hawkinsrgk]

Hi Randy

Just wanted to give an update on this

I tested freshly mixed reef crystals at 1.025. Not sure how high the calcium was but it tested at 500 ppm with salifert test kit. That is as high as my kit goes too. So it could be way above 500

Thanks again
Randy

 

[Randy Holmes-Farley Verified Community Expert]

Hi Randy

Just wanted to give an update on this

I tested freshly mixed reef crystals at 1.025. Not sure how high the calcium was but it tested at 500 ppm with salifert test kit. That is as high as my kit goes too. So it could be way above 500

It should not be much above 500 ppm at that specific gravity. You can test it, if you want, by using a second syringe of titrant and adding the two values together.