maintaining alkalinity

[rostervandross]

Hey everybody, I am trying to look into dosing for alkalinity. Currently I am just manually adding a two part solution and use much more of the alkalinity solution than calcium. Adding Alk manually is also causing swings and it usually gets down to 6 or so by the time I test and then boost it back up to 8 or 9, rinse and repeat.

I am wondering if I should start adding lime / kalkwasser into my ATO reservoir and how much to maintain the right level. My top off water reservoir is a 7 gallon wastebasket and I have about 80-90 gallons of total water volume.

 

[rostervandross]

Anyone recently go through this process adding lime/kalkwasser? Or other methods of keeping Alk consistent?

I'm looking for an alternative for now to buying a dosing pump and automating everything. I enjoy the testing and adding manually. And everything apart from alkalinity seems to be manageable or pretty predictable.

 

[rostervandross]

Bump

Trying to work out how much lime to add to my top off water to raise Alk a given amount

 

[chipmunkofdoom2]

Hey there rostervandross, do you test for Ca as well? What are your readings? Also, what salt mix do you use, and what are your test results when you test the newly mixed saltwater?

(I know this doesn't directly answer your questions, but the answers to the questions rely on this info).

 

[Big Pete]

Hi Rostervandross

i am at the same stage as you with my Alk, i put 1 teaspoon of kalk in to my 5 gallon ATO container as i though, well you need to start somewhere, after about a week i still have the alk swings.

i tested yesterday and my Alk was at 7.39 from 8.45, my CA was at 535 from 375 and my PH read 8.33 from 8.01, so it seems to have added too much CA and balanced the PH, but done nothing with the Alk level which was the reason i tried this.

so i now dont know how to move forward, if i put another 1/2 teaspoon in the ATO container will it continue to raise my CA and PH to crazy levels or will it all balance its self out.
i was dosing Seachem Reef Builder 1 teaspoon in RO water twice a week by hand and i feel to keep on the safe side i should go back to that.

I have heard lots of stories that tell you to be careful using kalk and maybe i should heed the warnings.

I would love Dave K to chime in here as he is a font of all that is good with Marine aquatics.

Cheers

Big Pete

 

[chipmunkofdoom2]

i tested yesterday and my Alk was at 7.39 from 8.45, my CA was at 535 from 375 and my PH read 8.33 from 8.01, so it seems to have added too much CA and balanced the PH, but done nothing with the Alk level which was the reason i tried this.

Hi Pete,

I was waiting for Rostervandross' response before judging his situation, but since you provided your information, I can give input on yours.

Kalkwasser is NOT designed to supplement alkalinity alone. It supplements both calcium and alkalinity at the same time. In reef aquariums, calcium and alkalinity generally both get used at around the same rate, and both usually drop at around the same rate as a result. If you need to supplement one, then chances are you need to supplement both (in most cases). Kalk is not good if you only need to supplement Ca or alkalinity: since it supplies both, you'll eventually end up with a correct alkalinity, but Ca that is way too high, or vice versa.

People say to be careful using kalk because many times it is used without fully understanding what it does (and because of the potential pH problems with overdosing.. but that's another story). There's nothing wrong with kalk and it's a great alternative to a Ca reactor if you can meet your needs with kalk alone. However, it's not a good choice if you have Ca/alkalinity stability problems, or only need one of the two.

This article has some great info on the topic. I would try switching to a two part dosing system and dose for whatever is low (Ca, alk, or both). If you're unable to get your parameters stable using a two part, then you may have a magnesium problem. Having low magnesium can affect the amount of Ca and alkalinity that you can get into the water.

Sorry to threadjack, Rostervandross. But I think the bit about kalk may be useful for you too. I wouldn't consider kalk unless your water chemistry is very stable, and you find yourself dosing the same amount of Ca as you are alkalinity.

 

[nanoreefing4fun]

This article has some great info on the topic.

This Randy Holmes Farley article is a great read !

 

[PSU4ME]

Good advice above. Let me tell you how I did mine and my progression to a ca reactor.

You first need to understand your water Params and it seems like you're off to a good start. Dose to an equilibrium of ca/alk/mg then test each day until a water change. This shows you usage and rate. Do a water change then test again, this shows what the water change adds back in to the tank. Knowing that, I break up the manual adjustments into two weekly doses. First two days after WC, second two days before WC assuming weekly changes. This worked for a while. Once you have that stability I started introducing Kalk in my ato. I used brightwells Kalk +2 which I highly recommend. The saturation of the mix you'll need to monitor but I was up to a tablespoon per gallon. The key was to have the ato set up so that it topped off often and not a whole bunch at once, with is really helped control ph swings.

Once my dosing because annoying due to the amount and frequency I got the reactor which is a whole other topic but worth it if you need it!

 

[rostervandross]

Hey yall a little busy at the moment I will stop back in here tonight and elaborate.

My latest readings were:

Alk 8.4
Ca 440
Mg 1200




Also got some magnesium chloride pellets and magnesium sulfate (Epsom) to make magnesium solution. The pellets also have calcium chloride and potassium chloride. Wondering how to measure doses

 

[DaveK]

You numbers are not bad at all, Leave things alone for the time being. Don't chase numbers. You will do a lot more harm than good.

 

[chipmunkofdoom2]

You numbers are not bad at all, Leave things alone for the time being. Don't chase numbers. You will do a lot more harm than good.

+1. Alk of 8.4 and Ca of 440 are perfect. Stability is much more important than certain numbers. Mg might be a touch low, but you don't want to go too much higher than 1,300 ppm on that either.

I'd just leave as is. If you need to dose alkalinity (like you mentioned in your first post) to maintain an alkalinity of 8.4, that's fine.. just dose a little bit every day instead of once every few days. That way, your levels remain stable.

 

[rostervandross]

Ok bueno thanks for assisting me. Can we keep examining it over the next couple weeks to see how I might set up a doser for my Alk solution (part 1 of 2) or kalk/lime solution? Because I'm just going to miss days of dosing alk every day

So last numbers were after dosing and parameters restocked up. Numbers after my water change and dosing two days ago were:

Alk 10
Ca 460
Mg 1420


Numbers today are:

Alk 7.3
Ca 460
Mg 1280

I will see how they do tomorrow and the next few days.

 

[nanoreefing4fun]

See what others say... but these alk swings are a real problem

 

[rostervandross]

Thanks man, yea that's what makes me want to add lime to my top off water, it is always putting small amounts in the sump since I don't have a doser.

I am using Red Sea Alk test

 

[chipmunkofdoom2]

Judging by your test results, kalkwasser will not work in your situation. Kalk supplements calcium and alkalinity at the same time. In your situation, it would probably keep your alkalinity levels stable, but it would send your Ca through the roof since your calcium numbers are fine. You need something that will just supplement alkalinity, like your two part solution or by adding baking soda to your topoff water. Whichever solution you go with, I would make sure to set it up in such a way that your alkalinity is the same every single day of the week. Unless your tank is empty, Glenn is right, these swings are very large.

There's not anything wrong with an alkalinity in the 7 dKh range, but the swings are the issue. Unless your salt mix gives you very low alkalinity and Ca from the get go, I would probably just shoot to get your Ca and Alkalinity to what your new saltwater mixes to.

Also, for the Mg pellets, you'll probably have to dose daily and monitor. If your Ca starts going up, then these pellets are providing more Ca than your tank is using. If that ends up being the case, I'd switch to a straight magnesium chloride supplement. It's likely that your tank will at least use some of the calcium, so you should probably be okay. I'd just keep an eye on it.

An additional though, it looks like your Mg is getting used pretty quickly as well (do you have a lot of coralline algae?). You'll probably want to supplement that as well.

 

[rostervandross]

Thanks chipmonk I appreciate the rundown

Today I got :
Alk 8.1
Ca 480
Mg 1240

You say baking soda raises Alk without affecting calcium?

Those readings include an entire tbsp of lime in my ATO that dumped 4 gallons in at once because of a snail on the float switch.



Last month I tested my two salts for pablomay's thread comparing brands of salt and I got:

I have the Red Sea test kit

At 77* and 1.025 salinity

Instant ocean reef crystals:

Alk 12.5
Ca 490+
Mg 1600


Seeachem reef salt

Alk 11.2
Ca 470+
Mg 1400

I suppose I could buy just one of the two part solution bottles but if that stuff is simply concentrated baking soda solution or something, I would rather mix some up. Mark up for bottled water type thing? Or is worth $19 a bottle? I have quite a bit of calcium solution left but running low on Alk.

I read around in that article and think I came across a section about nitrates messing with alkalinity. Another thing was that 'saturated' limewater raises 20ppm calcium per 1 mqL of Alk which is nearly 3 dKH.

And I am wondering- do people use a calcium reactor when the kalk wasser does not keep up with calcium depletion? Or does one switch to calcium reactor for strictly calcium and dose an alkalinity solution?


As far as the magnesium pellets and Epsom salt solution, all three of those compounds -magnesium calcium and potassium are safe and good? It feels weird dumping ice melter water in your tank. It is road runner pet safe magnesium chloride pellets- plant safe Eco formula stuff with just magnesium chloride calcium chloride and potassium chloride, water.
I have the seachem fancy pants brand "ions" magnesium supplement for now and it is not very concentrated it seems to me so I thought i could make my own once this one is done. I read that magnesium in the ocean is 10:1 magnesium chloride to magnesium sulfate in Epsom salt so I was thinking a hypothetical solution could have 10 tsp. mg cl pellets to 1 tsp. epsom. But then into like a half liter of water? Less? and pull 10mg doses out of that and test the tank to see strength/change per dose?

 

[rostervandross]

From the article: apparently alkalinity or hydroxide ions are used in the nitrogen cycle converting ammonia , nitrates etc.


Quote from article:
"For each ammonia molecule converted into nitrate, one hydrogen ion (H+) is produced. If nitrate is allowed to accumulate to 50 ppm, the addition of this acid will deplete 0.8 meq/L (2.3 dKH) of alkalinity.

However, the news is not all bad. When this nitrate proceeds further along the nitrogen cycle, depleted alkalinity is returned in exactly the amount lost. For example, if the nitrate is allowed to be converted into N2 in a sand bed, one of the products is bicarbonate, as shown in equation 2 (below) for the breakdown of glucose and nitrate under typical anoxic conditions as might happen in a deep sand bed." Randy Holmes Farley




It makes sense, two days ago my water change day I had 10.6 Alk and high ammonia, next test was 7.3 Alk and high nitrates no ammonia, today was 8.1 and lower nitrate. So consumed along the nitrogen cycle chain and we will see what happens next!

I am learning a lot it is good to test every day like this! see my tanks trend and learn what's going on with the chemistry and what exactly to dose