Question about Alkalinity?!

[Reel North]

Hi all

My tank is rolling along beautifully thus far (crossed fingers).

Ive been working from home, and have been fiddling with it every day ;)

I used a salifert test on Sat and my

Alk - 235
Calc - 470 steady (still there today)

I also dosed Alk on Saturday and the level went way up to 370.

But today (5 days later), it dropped all the way back to 270

My Magnesium was 1380.

Is this normal to drop like this?

And is there a way to "auto dose" it?

I also travel a lot and have this sneaking suspicion that I will be asking for help on dosing equipment soon.

So may as well ask now!

How do you all keep it level.

[gaberosenfield]

You should include units on any numbers you give. I assume that the calcium and alkalinity numbers are in ppm? If so, 235 ppm alkalinity = 13.16 dKH, which is already too high. It is dropping because it is precipitating out with something. You do not need to dose more, you need to stop dosing the Alk. You want to target between 7 and 11 dKH = 125 and 196 ppm alkalinity. Also, unless you have a significant biomass of hard corals, you probably don't need to dose calcium or alkalinity as long as you do regular water changes with good quality salt.

If you do have hard corals, you can buy a dosing pump with two heads and set it to dose pre-made solutions of calcium and alkalinity solutions to your tank. There are many options of dosing pump out there, just read some reviews. Unless you have massive calcium demand, you probably don't need to automatically dose magnesium because it is consumed at a much lower rate by corals than calcium or alkalinity. Just water changes will probably be enough to keep it up and, if not, you can always does the occasional magnesium supplement by hand.

[Reel North]

Sorry. its the readings from the salifert test. The Alk reading (forgot the decimal) was 2.35. went to 3.7 and now today down to 2.7. Calc is stable around 470.

[gaberosenfield]

Ok. Again, it is important to include the units with your numbers. Are those numbers for alkalinity in dKH or meq/l? It makes a big difference. If your alkalinity is currently at 2.7 dKH, it needs to come up for sure. If it is at 2.7 meq/l, it is on the low end of the ideal range and doesn't necessarily need to be raised. Look at your test kit's instructions and it will tell you what unit its readout gives. I assume your calcium is at 470 ppm because that is the only unit commonly used with calcium measurements. But you should ALWAYS give the units to avoid confusion, as highlighted in this thread.

Are you also dosing calcium when you dose your alkalinity? If so, the extra calcium could just be precipitating out the alkalinity, effectively negating the dose of alkalinity. Do you see any white precipitate when you add your alkalinity or calcium supplements?

[Reel North]

The ALK is mew/L. The calcium is ppm. Sorry it took us this long for me to copy the sheet lol.

I havent dosed calc at all since I dosed myself from 400 ppm to 480 ppm. The alk I dose on its own - its a 2 part dosing kit.

I dont notice any precipitating calc when I dose the ALK.

Why does it drop so fast?

[gaberosenfield]

Hmm, well that is strange then. If you aren't dosing any calcium and the calcium reading is staying the same, then I don't think the alk is precipitating out. I'm not sure why it is decreasing so quickly, but I don't think you need to worry about raising it either. 2.7 meq/l is within the optimum range, so I'd just leave it there. Maybe someone else will have an explanation as to why it drops so quickly after dosing.