Calcium,alkalinity,ph,brainache And Me.

[johnnyjtaylor]

Right here goes... I'm trying to raise my calcium,alkalinity and ph in my tank so I did a spot of reading on t'internet which made me scratch my head a bit,then bought some pots of expensive additives came home and started dosing to get the desirable levels.........

I bought some Seachem Reef advantage calcium(maintains magnesium and strontium) and Seachem Reef buffer raises ph to 8.3(and will also raise carbonate alkalinity). Before I started I tested my calcium 380ppm, then my ph looked like 8.1(liquid test kit colours are always fun)with a just before lights on morning value ph 7.9. I didnt have a KH test so didn't do that(obviously). Anyway I dosed calcium first getting it up to 450ppm over a few hours then did the buffer a couple of hours later which raised the ph to a colour on the test kit that looked more like 8.1 than my initial reading of 8.1(I've ordered a digital ph meter now!!). All seemed well and I retired to bed a happy reefer......
The next morning I checked the ph and the before lights level was about 8.0(liquid test kit wise) and was pleased at the improvement and hit the tank with another dose and left it well alone.
The third morning the ph was 8.1ish "cool" I said to myself. I got a KH test and tested it that evening 6.1 dKH a bit lower than expected.
Today the morning ph was still 8.1 and I tested the calcium 400ppm so I dosed the calcium again to get it up, this seems to have the effect of lowering the dKH to 5.4 and so my confusion begun........
So Questions:
1. does the calcium lower the alkalinity and alkalinity lower calcium?(obviously their related)
2. will I reach a happy medium?
3. Is there something that would do the job better than the seachem stuff I bought?

thanks johnny

 

[SkiFletch]

If only reef chemistry were that easy... If you really want to tweak with chemicals, you can't just consider calc and alk, you need to also monitor magnesium. Also, a pH swing of 0.2 from lights off to lights on isn't the greatest thing ever, it's boarderline. 0.1 would be something to shoot for. Perhaps a little more surface agitation is possible? Also could just be trouble with a sealed winter climate and high ambient CO2 levels...

Back to the magnesium thing in as laymans terms as I can offer. Mg at natural sewater concentrations, or higher than NSW, will act to slow down the reaction of Calcium and Bicarbonate ions which try and form insoluble Calcium Chloride solids. Calcim Carbonate solid "wants" to form when there is an imbalance of calcium and alkalinity. Magnesium "occupies" cabonate and bicarbonate ions to prevent them from reacting with calcium.

So were I you, I'd buy an Mg test kit, see where you're at and go from there.


Out of curiosit,y what corals do you have and why are you dosing?

 

[johnnyjtaylor]

Thanks Ski, That makes sense I'll get a mg test kit asap. I want to raise the ph as I want to add some xenia,I had some when I first started my reef and it slowly 'grew down' as it were and disappeared and after a bit of reading low ph is a major factor in this.

Out of curiosit,y what corals do you have and why are you dosing?

I have some LPS frogspawn/brain/candycane(the candycane being unhealthy and you advising me to keep calc and alk up)

cheers Johnny

 

[SkiFletch]

Ah yes, so you do have some calcifying corals in there. Is your tank jam packed with coraline algae or no?

 

[johnnyjtaylor]

Having just moved house (4 weeks)and using a different tank to what I was before the tank itself isnt but the rock(20kgs) is heavely encrusted in coraline algea. I,ve put a sweeping powerhead on its side at the top to increase agitation and ordered a mg test kit(salifert) with some mg additive(seachem).
My dKH is still 5.4 which I gather is way to low,so I hope the mg test arrives tomorrow so I can see whats going on.
cheers johnny