Dosing Strontium, Mg, Ca, Alk

The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.

Floyd R Turbo

Aquarium Advice Addict
Joined
Feb 7, 2009
Messages
1,682
Location
West Des Moines, Iowa
The reef tank I maintain has always needed Alk dosing, I've been using Brightwell Alkalin8.3-P and Seachem Reef Advantage Calcium also. Recently I started testing Strontium and Iodide/Iodate (both Salifert) and those are pretty much zero, so I bought Seachem Strontium and Seachem Iodide. I also bought Seachem Magnesium.

Q #1: As far as Alk, Ca, and Mg go, there is a maximum daily dose. Obviously for Iodide, you don't want to overdose either. But Strontium says nothing about a maximum dose. I figured that I would have to add the entire 480mL bottle to get the Strontium level to around 11. Would that be a bad idea?

Q #2: Mg, Ca, and Alk dosing. Both the Ca and Mg bottles from Seachem say that you should not dose these on the same day as Alk, or at least 30 minutes apart if you have to. Is this the general rule for all Alk dosing products in relation to Ca and Mg? Is this just something I am going to have to deal with, or is there a way around that? I assume it doesn't apply to a drip system, since you're not adding a lot at once?
 
Good article with Randy Holmes-Farley's opinions on dosing...

Reef Aquarium Water Parameters by Randy Holmes-Farley - Reefkeeping.com

Quick summary is that he doesn't recommend dosing Iodine because of the inaccuracies of test kits. If you're doing water changes, most likely your iodine levels are not close to zero. Same goes with strontium.

Regarding the ca/alk dosing - it is recommended to space the dosing of calcium and alkalinity apart so that you don't precipitate out the calcium component. The alkalinity portion will temporarily increase the pH of the surrounding water - this is the cloud of white you see when you add the alkalinity solution to the tank. If you were to add the calcium component to the high pH water, you could end up precipitating out the calcium - think miniature snowstorm. No big deal... except you end up losing all the calcium that you're trying to put in. This is the same reason you can't mix the two components together.

With that said though... I've never used the Seachem stuff, but when I add my 2-part solution, there's a whole whopping 10 seconds between my alk and cal doses. I take about 10 seconds to pour my 30ml of alkalinity solution into a very high flow area. Whatever "high pH cloud" appears dissipates very quick. I then rinse out my dosing cup with tank water a couple times and then fill it with 30ml of calcium solution. That gets dumped in about as fast as the alk solution. Whole process takes me about 30-60 seconds in the morning. You want to dose in the morning, when your pH is the lowest as you'll see a temporary increase in your pH.
 
When I used to make up the 'stock' solution of Alk and administer that, I would see the white cloud effect. Since then I figured out that if I just put 2 tsp (8g) into a 1 quart jar, fill with RODI, and shake for 10 seconds, I get the same dosage. When I pour that in, I do not see the white could. I normally just pour it into the sump, but I probably could pour it directly over the return pump area and then it would blow into the tank and the powerheads would distribute it well enough. Then I could add the Ca or Mg into the open area of the sump (40B with about 20g in it) and it would distribute more slowly in the DT.

As for the inaccuracies of Io test kits, this is what Salifert has to say about it:

  • Iodine is present in natural sea water in a very low concentration (0.6 mg/L or 0.06 PPM) and this iodine occurs as several different species including iodide, iodate, molecular iodine and hypoiodite.
  • There is a misconception among many hobbyists that iodide predominates in natural sea water but in fact, it is iodate which is the predominant element.
  • Test kits which are not capable of detecting iodate are not suitable for aquarium use, since in a properly functioning tank most of the iodide will be transferred to iodate and any test kits not able to detect iodate will give a false, low iodine reading.
  • Iodine test kits should be capable of measuring all forms of naturally occurring iodine. The Salifert Test Kit is the only one offering this feature, measuring all naturally occurring iodine compounds and giving a reading of total iodine concentration.
  • Unlike many other test kits, the Salifert Iodine Profi-Test is free from interference from other elements found in saltwater, which means the results obtained are very accurate.
  • Color remains stable for several hours.
  • Scale goes from 0.01 - 0.15ppm and optimum level is 0.06 mg/L.
  • Can provide up to 40 tests.
  • For marine use only.
Note: Use of so-called time released iodine supplements or supplements containing organically bound/complexed iodine species will give false results.

The presence of strong reducing substances such as ascorbic acid will also give false value. Some supplements do not contain ascorbic acid. Dechlorinators are also strong reducing substances.

My question would then be, is the Seachem product organically bound? It says "potassium iodide". Maybe I should be dosing with Salifert's Iodine product, if I do at all.

My main reason for wishing to start dosing these is because I do not do water changes on this tank, since it has an ATS. Actually, I didn't need to do them before the ATS, there's probably 3 lbs LR/Gallon and it's well established.
 
Just read that whole article. Very informative, thought I had read it before but maybe I didn't read the whole thing. Interesting that Nitrite is not toxic in the marine aquarium. I don't think I could achieve 100 ppm Nitrite if I tried.

I guess I can stop the Iodide dosing, maybe just once or twice a month (the bottle suggests twice a week)

As for Strontium, good to know that there indeed is a toxic concentration, but 38 ppm is off the scale of the Salifert kit. I think I'm going to have to mix up a fresh 5g batch and test the Io and Stront to 'calibrate' the test kit.

After reading all of that, I definitely will be ordering a 2-part solution from BRS. I think I have enough data (several month worth of 2-4 tests/week) to determine the required dosing level of each, then I can just let the owner know what he needs to do (and hope he does it)
 
Oh yes, it is marvelous...hard to tell but I think I detected sarcasm. ...

LOL... yes, you did! I can sit on my hands pretty good about ATSs because they're just another way of skinning the cat. But when it morphs into discussions about doing away with water changes, that's when my "santamonica twitch" starts kicking in. :)
 
yeah, I'm trying not to become a Kool-Aid drinking algae farmer. If I didn't want to does Stront and Io, I could just do a monthly 10-15g PWC and siphon out the sump, and that would 'probably' keep the levels up, but when I test Strontium at least 5 times in a month, even after a 20% PWC (like 1-2 days after), and see 0-3ppm, and same with Iodine, I started to wonder if it was even worth bothering with the PWC at all if I was going to have to start dosing these back in again. So I'm not that worried about Io, though I would (out of sheer curiosity) try to get Stront to about 10ppm and see how fast it drops, so at least I know what is going on.

As for Mag, Cal, Alk, there's no getting around the fact that I will have to dose these things regardless of whether I do PWCs or not. I would even have to up the Cal of the fresh RC mix 'cause it's too low even at salinity 35. The only other benefit I see of the PWC when you have no N or P (besides cleaning the sump) is replenishing trace and I'm sure there's other added benefits, but there are plenty of people who keep everything under control and never do PWCs.

I just think it's a cool concept to never have to change any of the water, saves a lot of $ and time. Not saying that there isn't another way to achieve this, but this is one way and I would like to make it work to the maximum effect.

Now excuse me while I down this Kool-Aid. It's green by the way. Just like my Algae. LOL
 
Last edited:
Back
Top Bottom