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Discoloured Macro Solution

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KirstyF

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Hi All

Quick query re my macro solution.

The last two mixes that I’ve made up have become discoloured after around 2 weeks.

I normally only make up enough for around 3 weeks or so at a time and I add potassium sorbate and ascorbic acid as per the IFC calculator. Previously my mixes remained completely clear.

Last mix, I threw away, gave the bottle a really good clean and made a fresh batch but it is discolouring again. Just want to check what might be causing this (Wondering if either the bottle or one of the salts is contaminated) and is it safe to use?

The bottle is kept at room temp in the aquarium cabinet so not in complete darkness, as the back of the cabinet is open, but it’s pretty gloomy in there.

The only thing I have changed is to increase the Po4 content.

828B175C-6E16-41DB-BF51-8810BDABB103.jpeg
 
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My present AIO always discolour due to the Iron (Fe) and when I was using Macros and Micros the Micro discoloured again due to the Fe and the Macros also had a slight discoloration to them as well but not as dark as the Micros- similar to your pic
 
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GHNelson said:
:confused:Revert back too the original recipe see what happens!
Click to expand...

I’ve increased Po4 to help combat the slight GSA issue. So far, it’s not been a miracle cure but I’m keen to keep that going for a bit so that I can assess whether or not it’s really helping. Give it a few weeks then maybe dial it back and see if GSA increases.

Might try the next mix without the potassium sorbate and ascorbic acid and see if that makes a difference but so long as the slight off colour is nothing to worry about, I’ll finish up this batch.

My Micro is very dark, looks a bit like Coca Cola, but it always has, so I’m assuming that’s just the Fe effect.
 
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Are you using APFUK salts by any chance?

I had the same thing happen to my macro mixes. It’s a reaction between the ascorbic acid and impurities in the macro salts.

Ultimately you don’t really need to add Ascorbic acid to the macro mix (it only really helps with the micro mix), just potassium sorbate to prevent mould, but I don’t think the discolouration is a major issue for the macro salts anyway.
 
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KirstyF said:
I’ve increased Po4 to help combat the slight GSA issue. So far, it’s not been a miracle cure but I’m keen to keep that going for a bit so that I can assess whether or not it’s really helping. Give it a few weeks then maybe dial it back and see if GSA increases.

Might try the next mix without the potassium sorbate and ascorbic acid and see if that makes a difference but so long as the slight off colour is nothing to worry about, I’ll finish up this batch.

My Micro is very dark, looks a bit like Coca Cola, but it always has, so I’m assuming that’s just the Fe effect
Click to expand...
Yes, Fe will colour the Micro solution!
 
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Wookii said:
Are you using APFUK salts by any chance?

I had the same thing happen to my macro mixes. It’s a reaction between the ascorbic acid and impurities in the macro salts.

Ultimately you don’t really need to add Ascorbic acid to the macro mix (it only really helps with the micro mix), just potassium sorbate to prevent mould, but I don’t think the discolouration is a major issue for the macro salts anyway.
Click to expand...

I’ve got some APFUK and some from aqua plants care so a bit of mix and match. Neither supplier had everything I needed in stock when I was buying!!

Re-assuring to know it’s nothing to worry too much about though.

So maybe stick with the potassium sorbate and just cut the ascorbic acid. I’ll give that a go next time round. 😊
 
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You don’t need to acidify the Macro, if you are keeping the solution out in the open and under illumination the discolouration could be due to photo reduction of the Ascorbic acid and formation of byproducts in reaction with the Sorbate that tint the water, any reaction products will be very limited and the nutritional content of the solution will remain largely unchanged,

:)
 
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