Iron - When is there enough

[cspell]

Reading the Flourish Iron page it says we want to try and maintain about 0.10 mg/L of iron in the water.

So the last few days I've been testing my iron and trying to get there. According to the dosing instructions I should be adding about 0.5 ml of Flourish Iron daily for my small tank. Well, today I added 1ml this morning and 1ml this afternoon (2ml today) and tested this afternoon a few hours after the 2nd dose.

No iron present in the water.

After reading the forum you tell us that the plants will consume it quickly. Yep, that's my experience. :-)

Which is good. I would say I have a heavily planted tank at this point. Before I had this many plants i was able to measure iron in the water. I thought I was adding too much iron at one point so I had cut it down to 0.25ml. But since adding the new plants I started testing again and found 0 and haven't gotten above 0 yet.

So the question is: Should I keep dosing iron until I see 0.1mg/L since the plants seem to be consuming everything they can get? I am seeing some signs of iron deficiency in the plants so my thoughts are to keep going until I see some left over iron in the water.

I have an all black flourite substrate and there are some Flourish tabs in there somewhere. They got lost in the last planting. So I need to go add some more for the new plants. I imagine that will help as well. I'm also using Flourish, Excel, and FlourishTrace. Excel every day and alternating days of Flourish & Trace.

Oh, I was seeing a build up of brown algae and noticed that I had higher than wanted phosphate levels so I got an Oto and put Phosguard in the filter and now that problem has gone away, rather quickly I might add. :-) So needless to say my phosphate level is 0 now. Should I take the Phosguard out so some phosphate will build up for the plants?

Thanks as always for your great products & help!

Chris

[Tech Support EH]

Hi cspell,

You are correct; because Flourish Iron contains iron in the plant- preferred oxidation state, which is ferrous iron (Fe2+), plants utilize it immediately, especially in high-growth situations.

The first thing that I would suggest is to test the reference solution that is included in your iron test kit. Doing so will rule out a test kit error, and this will also ensure that you are not overdoing it on the iron. I would hate for you to continue dosing and dosing in order to see a reading, just to find out that your kit was not functioning properly. I highly doubt that this is the case, but it will ensure that you do not induce iron toxicity with continued dosing.

If indeed the kit is giving an accurate reading, then you can increase the amount and/or frequency with which you are dosing Flourish Iron. Since some of your plants seem to be exhibiting signs of iron deficiency, then slowly increasing the amount of iron that you dose is completely safe, as it will not linger in the water column.

Beyond that, your dosing regimen looks great. As far as phosphates are concerned, there is obviously a fine line between enough and too much. It's best to try and maintain a phosphorus level of 0.05mg/L in a planted tank, which equates to 0.15mg/L of phosphates. As long as the algae is under control, then you can remove PhosGuard from the filter, so that there is some available for your plants.

Have a nice afternoon.

[cspell]

I did check my kit to make sure it was registering the iron and it sure is. Good to check though.

This afternoon I added another 1ml to the tank and 15 minutes later checked it and found I had somewhere between 0.25 mg/L to 0.50 mg/L. Then I checked it about 45 minutes later and it was back to 0. So something is eating up the iron quickly.

I don't want to overdose so I think I will stick to just adding 1ml in the morning and 1ml in the afternoon of iron. That's 4 times the dose for my volume of water.

I do think I notice that the brown algae is starting to grow again. I hope I'm not feeding the algae. My PO4 is still 0.

[Tech Support EH]

That sounds like a good plan, cspell, as you certainly don't want to overdo it on iron.

Algae can take advantage of the high lighting and nutrient content in planted tanks. Just be sure to keep a good eye on your phosphates, nitrates, and dissolved organics, as these are major contributors.

Have a nice weekend!