All in one acetate based dosing solution

[Matt VDB]

Hi everyone, I've been working on an acetate-based solution to simplify my reef supplementation over the past few weeks and would love some input (especially by Randy).

Background
I've made a solution containing 1 molar calcium acetate, 0.1 molar magnesium acetate, and trace strontium, barium, Iron, manganese, copper, zinc, chromium, nickel, cobalt, iodide, potassium, bromide, fluoride. The idea was to supplement everything I thought was important in one concentrated solution as to simplify my system in the long run. As so far, there are no issues with precipitation and everything seems to hold as it should which is great. I have a couple of ICP tests to run to confirm the trace element stability and I imagine this should be okay too.

The issues
There is always a trade-off to any method we use and the big one here is the amount of carbon I inject into the tank. Acetate is this carbon source. As acetate is essentially only 2 enzymatic steps away from being fed directly into the citric acid cycle, there is a very quick metabolic response. This is great if you have an overstocked tank and need significant nitrate reduction, but in my tank, this caused a nitrate crash and bacterial bloom after 7 days. To clean the tank up I've stepped my ozone injection up and added a flocculant to remove excess free-floating bacteria through polyester wool and the protein skimmer. Additionally, I have not started dosing calcium nitrate to bring the tank back up to 2.5 ppm and would eventually like to stabilise this at 5 ppm (I would usually prefer potassium nitrate, but this is what I had in the house at the time). I have a 600L tank filled with SPS and expensive LPS so it is important I don't make too many mistakes going forward.

Questions
1) Do you think I should add nitrate directly to my dosing solution and balance N to C according to something like the Redfield ratio? Ideally this would prevent bottoming out in the future.

2) Are there any phosphorus sources I could also add to prevent a potential bottom out? Adding something like potassium phosphate will likely precipitate out calcium phosphate so I don't think that's an option.

3) How bad would it be to swap the magnesium acetate for magnesium sulphate? Perhaps this will reduce bacteria growth a little bit, although we are only dealing with a 10th of the carbon source I think the issue is excess carbon. Alternatively, I could do a 50/50 mix etc.

4) Is my method doomed to fail regardless? I think this can work with the right filtration and it could be just something that some tanks have issues with while others don't experience the same problems.

Any suggestions would be great!

 

[areefer01]

Putting aside your question for a quick second is there a reason to go the DIY route than purchase an over the counter solution that is already available?

 

[Matt VDB]

Putting aside your question for a quick second is there a reason to go the DIY route than purchase an over the counter solution that is already available?

My location, cost, and curiosity. In New Zealand, products like All-for-reef are very expensive and are rarely available. The hobby isn't very big here compared to Australia or the USA so we often have issues getting the same products other reefers have reliably. There's other reasons too such as a lack of potassium in AFR that pushed me towards a novel DIY, but that's just a minor thing.

 

[Matt VDB]

@Randy Holmes-Farley

 

[Randy Holmes-Farley]

IMO, this is a fine plan with the caveats you mention. Salifert All in One is a similar product.

The bacterial issue is the main one, IMO.

If you shift magnesium, the chloride is a better choice than the sulfate, and a mix like my diy mag supplement is optimal from an ion balance perspective.

Putting nitrate into the mix is an ok plan. You could also use ammonia if you dose slowly.

I do not think there’s an easy way to put P into this mix.

 

[Matt VDB]

Thanks for getting back to me Randy!
I found an old article you wrote that I really enjoyed reading (the link below). I think that really does put it into perspective a bit better. Ultimately, most people won't see much greater than a 0.5% increase in chloride with minimal water changes and very high dosing. I think a 5:3 MgCl: MgSO4 mix could be very good so long as I don't have a major calcium precipitation issue. In principle, if I use a 5:3 ratio I would have approximately 0.06 molar concentration of sulphate and the solubility of calcium sulphate is much higher than that I believe. Taking this into account, I think I might move away from magnesium acetate. To be fair, it is the most expensive part of this (approx. $90 NZD per kg) so it would be better to use your method.

This makes me wonder if the balling method really requires the ion balance mix..

Anywho, if I were to give this new solution to a couple of other local reefers and didn't want their nitrate to bottom out. Is there an idealised ratio of nitrogen to add to calcium acetate to keep a steady state or will this be too hard to guess? I'm aware that other products have done something similar but I don't have the details on the amounts they used or their rationale.

Cheers!


(https://reefkeeping.com/issues/2006...alts and,this purpose what those designations)

 

[SaltySaltySoup]

Nearly a year on, how’d you go with this? I separately had the idea and googled until I found this post.
Just remembered that in school they taught us that acetate salts are Always water soluble.

 

[Randy Holmes-Farley]

Nearly a year on, how’d you go with this? I separately had the idea and googled until I found this post.
Just remembered that in school they taught us that acetate salts are Always water soluble.

One concern with acetate dosing is the very large organic carbon dosing effect if the alk and calcium needed is on the higher end.

Suppose you have a typical tank using 1.4 dKH (0.5 mM) of alk and 10 ppm of calcium per day.

If you dose that via calcium acetate, it adds the equivalent of 59 mg of acetate per liter of aquarium water, which is like adding 223 mL of vinegar a day to a 100 gallon tank.

That amount is likely quite a bit more than most folks want.