Dosing Ferrous Fumarate

NeveroddoreveN · May 31, 2020

BACKGROUND:
I have a chaeto tumbler but my growth has stalled. I decided to purchase the giesemann iron test. My first iron test result was a big, fat ZERO.

WHAT I DID:
I followed Randy's recipe for ferrous gluconate, only using ferrous fumarate. I was a little more generous, bc it was at zero.

RESULT/QUESTION:
24 hours later the test still reads zero. Is it being consumed that fast by the chaeto? Does ferrous fumarate not show up on a test? Is human error the most likely?

Randy Holmes-Farley · May 31, 2020

I do not generally recommend dosing enough to detect by kit. They are just not sensitive enough. Even icp can barely detect the amount I dosed, which was Way more than NSW levels.

It also depletes very fast as it precipitates and organisms consume it.

Dan_P · May 31, 2020

NeveroddoreveN said:
BACKGROUND:
I have a chaeto tumbler but my growth has stalled. I decided to purchase the giesemann iron test. My first iron test result was a big, fat ZERO.

WHAT I DID:
I followed Randy's recipe for ferrous gluconate, only using ferrous fumarate. I was a little more generous, bc it was at zero.

RESULT/QUESTION:
24 hours later the test still reads zero. Is it being consumed that fast by the chaeto? Does ferrous fumarate not show up on a test? Is human error the most likely?

A couple of ideas.

Your iron test may not be detecting iron.

Iron can disappear pretty quickly from the water when it is in the aquarium, but can last longer in a sample of aquarium water.

First, mix iron fumarate with either fresh salt water or tank water. Confirm the test method will detect iron when it is chelated with fumarate.

If your test method does work, dose the iron fumarate and start measuring the concentration in the water after the dose has had time to mix and then every 3-6 hours afterwards until you have had enough testing or the iron is undetectable. At the same time sample and test the skimmate if you have a skimmer. You will have to empty the cup before you dose and then again after each measurement. The skimmate measurement may show substantial amount of iron.

As for the Chaeto growth, what are the nitrate and phosphate levels?