confused on dosing...

[amber3k]

So for the last week I have been checking my levels of mg, alk and cal. My mag had no change, my alk changed by 0.1 over the span of five days and my cal went down 10. I evaporate roughly a gal of water daily. If I was to dose kalk, how do I figure out how much? I'm a visual person and all these equations are bungled up in my head!

 

[Icefire]

0.1 what? dkh?

 

[bertoni]

There are a number of units for measuring alkalinity, unfortunately, so specifying the unit here would be useful. dKH or meq/L are the more common units.

Whatever the units are, that's a very low rate of consumption. I might just add ½ tsp of Kalk per gallon, and see how that goes. Even that might be too much, but every tank responds differently. Part of the issue is that Kalk tends to increase the pH, which often encourages significantly more growth, so consumption goes up.

 

[amber3k]

dKH...im sorry I didn't specify that one...

 

[bertoni]

Okay, that's a very small change. I might reduce the dosing to ⅛ tsp, but ¼ might be fine.

 

[Icefire]

At 0.1 dkh I would not dose, those number are within the error level.

Do a manual dosing every few days/ once a week

 

[bertoni]

That's a reasonable point, too.

 

[downbeach]

What are your Ca, Mg and Alk numbers? At what SG? What test kit or device are you using to do your measurements? I would do a series of measurments over a few days to get a trend line. Or hobby grade test kits have a certain margin of error to account for, and trying to make an true assessment with one test is unlikely. As an example in a perfect world, assuming your Ca reading to be accurate, your alkalinity should have shown an use of ~1.4dKH.

 

[amber3k]

Ok...some back ground first...I initially used reef crystals and never had an issue with my numbers. Lfs stopped carrying it and so I was buying instant ocean instead. Thats when numbers started falling. I have switched back to rc and I'm dosing a little superbuffer-dKH daily to get my numbers back up and then will dose cal when alk is up. I'm hoping rc will keep my numbers good after that but looking into my dosing options just in case. I haven't tested today but as of yesterday mag is 1400, dKH is 6.2 (low! I dosed yesterday and will check again today) and cal is 390, also low. I have 150g dt and 55g sump. Lps and softies, not heavily stocked on fish or corals, but coraline is really taking off.

 

[downbeach]

Ok...some back ground first...I initially used reef crystals and never had an issue with my numbers. Lfs stopped carrying it and so I was buying instant ocean instead. Thats when numbers started falling. I have switched back to rc and I'm dosing a little superbuffer-dKH daily to get my numbers back up and then will dose cal when alk is up. I'm hoping rc will keep my numbers good after that but looking into my dosing options just in case. I haven't tested today but as of yesterday mag is 1400, dKH is 6.2 (low! I dosed yesterday and will check again today) and cal is 390, also low. I have 150g dt and 55g sump. Lps and softies, not heavily stocked on fish or corals, but coraline is really taking off.

I have used both successfully, but RC does have higher levels of Ca, Mg and Alk. So, if using plain IO you will have to do a little more supplementing. Since the mean average of the worlds SG is .1026(35ppt) that is the target I always used for a reef tank. If you keep it lower then you can expect to get lower Ca, Mg and alk numbers too...possibly needing more supplementing, since you are adding less salt mix to begin with. The typical uptake of Alk and Ca is a ratio of about 5 parts alkalinity to every 2 parts calcium, which is to say 2.8dKH(50ppm) to every 20 ppm of Ca, this includes any stoney type coral, clams, coraline algea, etc. Any two part supplement product/recipe is designed to provide that with equal doses of each supplement. I would keep an eye on your alkalinity since it uses more, and there is less in reserve in your system to begin with, and base your possible dosing on that. Depending on your WC schedule/amount it is also possible that with those WC's there may be enough Ca and possible Mg to keep up with your current demand...meaning you would only have to dose the alk part for now. So, keeping your SG at a level you want, and doing regular WC's while checking your systems needs will give you a good starting point.

 

[amber3k]

Thank you. I keep sg at 1.025 and wc 10% every ten days.

 

[outssider]

Ok not heavily stocked on fish or corals, but coraline is really taking off.

coralline algae can really start to eat up your alkalinity/calcium. consumption will constantly increase as time goes by until your tank is full of coral and coralline then it will level off.

 

[bertoni]

Coralline can run through 2-3 dKH per day, in my experience.