Alk & Calcium swings ... Need some insight

[Danroth]

When I finally got my first alk kit & tested, my alkalinity was 5; not horrible, but not good either. I immediately went and got some ESV 2 part dosing, and started, and I've been keeping a log book ever since to try and get things in check.

Generally, I get home from work about 7pm, and then I do all my water tests. And, generally when I test, my alk is at about 6.0 at that time. I dose about 4 oz, retest later on and it's 8-8.5, and 8.5-9 is my target. According to the calculator I use, 420 is the desired/balanced Calcium for that alkalinity and everytime I test at night it's around 380-390.

My tank is new; just about 2 months old. I have a monti frag in there, a frag of acropora, an acanthophylia (meat coral), ricodera mushroom, 2 zoo's and an acan lord small colony. I also have coralline algae starting, but no real good growth yet on the rocks; just spots here and there.

So last night, I dosed what I normally do, and then this morning checked; figuring maybe I could do a partial dose in the morning, and another partial dose at night. I tested, found that my alk & calcium were both at the same levels as they had been the previous night. Tested just before noon, and I'd only dosed 16-ish hours previous, whereas I would normally test roughly in 24 hours.

It is now 7pm, and I retested, and everything is where my 'goal' wants it to be.

So I am wondering; is it possible or probable that coral only takes in calcium at night (or, when my lights are off) when they generally open up to feed? Anyone else have something simliar like this happen?

Also, with a new tank, I'm also wondering if the acanthophylia, small acan frag/colony, small frag of acropora & the coralline algae would make up for the 4oz of alk and 6oz of Calcium I'm dosing every night?

My Magnesium is steady at 1300-1350, so no worries there. Salinity is a rock solid 1.025 everytime I test.

Phospates, Ammonia, Nitrate, Nitrite, all undetectable or 0.

Just trying to get a grasp on dosing here. If more info is needed, I can provide a day-by-day dosing & test results from the last week.

 

[ritter6788]

I think you're doing the right thing. Constant testing and dosing accordingly will help you figure out exactly what your tank needs. Be careful not to dose cal. and alk at the same time to avoid precipitation.

 

[islander84]

Dosing kh from 6 to 8 or 8.5 in a few hours could cause alot of stress on your corals. The reason your tank is using so much alk and cal is because its new, your subtrate will absorb things until it finds its balance point, also while your tank is going through its coraline algae bloom phase you will notice your mag will be consumed alot more than usual.

Try dosing in small and slow dosages to keep things stable

 

[islander84]

What size tank are you running

 

[Downbeach]

The uptake of Ca and Alk, by any "stoney" corals, coraline algae, etc., is 20 ppm Ca and 50ppm(2.8dKH) Alk(CaCO3), which is a ratio of 2 pts Ca to 5 pts Alk (2:5). Equal dosing of two part supplements, i.e. ESV, are designed to provide the same ratio's. Saturated kalkwasser also contains this same ratio, @ ~ 800 ppm Ca(2pts.) to 2,000 ppm CaCO3(5pts.).
If you're using a "reef" grade of salt mix, i.e. Reef Crystals, I'd make sure my salinity is right, by measuring it using a calibrated refractometer, or calibrated metering device. If you're using a swing arm type of hydrometer and it's giving you bad information, you may not be adding enough salt mix, which means that you're also not adding enough of the other elements as well, i.e. Ca, Mg, etc. and you'd require more dosing. With normal WC's at the a salinity of 1.026, I've never had to add Mg, using this type of salt mix.

After checking your salinity, I would get your param's up to where you want them, i.e. Ca @ 420, Alk @ 8, etc. and then monitor the use between WC's to determine your dosage, and then start dosing in equal parts of the a and b supplements.

 

[Danroth]

Thanks for the advice, so far.

My tank is 125; I've started taking tests at different parts of the day, and I am dosing as needed, more often and in smaller doses, as of yesterday, and today. When I'm working I'm going to start testing, and dosing both in morning, when I get home from work, and before I go to bed until I can get an idea of some stability, and exactly what amounts per day I need to.

I am also using a calibrated Milwakee Refractometer, love that thing. My salinity is stable, everytime I check it, at 1.025.

Keeping a logbook, too, of any/all changes or additions to the tank, so I can backtrack. Also realized that dosing into my DT at my return was a bad idea, and probably the reason my acro is dying. Got that issue fixed, before it really did some damage.

I don't mind making mistakes, just as long as I learn from them now, rather than later, when I have a tank set up for 2+ years. Appreciate all the help I've gotten here, so far.