Iron is pegged but where did my reds go?


Junior Poster
Nov 28, 2008
Denver CO
I recently switched from dosing the suite of Flourish products to dosing Chelated Iron, KNO3 and KPO4 but I am still using the classic flourish and excel. This is a high tech tank with 200+ par throughout the tank, lotsa CO2 and flow, my values are
I can't understand why I am getting the worst reds even though the iron is higher than its ever been. My formerly brilliant red plants include Ludwigia guinea, Nesea red and Polygonum SP.

Additionally, my narrow leaf stellatus is picture perfect with 1/4" internodes, 1/2" stem and 6" diameter but my Eichornia, Eriocaulon setaceum and Tonina are noticeably stringy with long internodes and thin stems.

What is going on guys? Am I missing something? I have some thoughts but I am interested to see what you come up with.


Plant Guru Team
Lifetime Member
Sep 23, 2007
South Florida

Could you please provide some more specifics on your tank size and dosing and maintenance regimen, substrate used, etc?

How are you measuring 'lots of c02'? Are you using a drop checker to help determine this? How do you diffuse c02 into the tank?

How much flow/current do you have? Are your filters clean and sufficient for the tank size/inhabitants? What is your lighting duration?

If you have some species doing well and not others, I would suspect low or unstable/insufficient c02 and nutrient levels.

Nutrients are easier to rule out by increasing dosing and ensuring there are no limiting levels of nutrients. Are you dosing per the EI regimen?

If you dose per EI the 50% weekly water change (or more up to you) allows folks to dose 2-3x the recommended dosage for their specific tank as the water change will reset the amount of nutrients in the tank. remove waste products, and add c02 and trace elements to the tank.

What is your plant bio-mass? Could your tank need a trim so that flow of nutrients to all plants is affected?

Also, if you have >200 PAR all over the tank, that is a tremendous amount of light and will cause a huge need for carbon (c02) and other nutrients. Are you supplying them in sufficient quantities?

Have you confirmed this with a PAR meter?

Have you calibrated your test kits recently? How accurate are they? Hobbyist kits are not that accurate so your readings could well be incorrect. Many folks get caught by inaccurate test kits and think the levels are adequate but are not......

Sorry to ask so many questions in return but details are important to give advice for your particular issues.


Guru Class Expert
Feb 17, 2007
Lincoln, UK
200+ PAR is a huge amount of light and I'm pretty certain it won't be 'throughout the tank'

Possibly at the surface but not 'thoughout the tank'

Tank size and lighting type/wattage would be very interesting to know :)

I'm not overly sure on the Fe theory here. sounds like a myth to me but then I don't know for sure. lol!!!

Here is another thread where there is a small discussion about it:


Tom Barr

Staff member
Jan 23, 2005
Assuming the parameters are tested are correct, they have been measured against known standards.

I'd add about 4-5X more PO4.

NO3 can change the color of some species as it gets lower, adding more PO4 will can drive the NO3 lower as can more CO2.

Still, I get excellent color without low NO3. So it can be done.

Your CO2 may be a bit low from the sounds of it, Tonia is a good indicator, you have a ton of light, so that's not a factor. What type of sediment do you use?

GH seems good but might be a bit lean on Mg.

If you have some plants doing well, and others not, often times this i a CO2 issue.
You hear a lot about cometition with algae and plants. In the real world it's mor eoften between two plant species for light and CO2.

We prune to address the light issue, add more/less etc.

Can you adjust the light up about 4-6"?
That should help.

You can also add more CO2, drop the pH down another 0.1pH units and see for a week or so. Then another and keep an eye on things. It might take 1-3 weeks for responses.

The less slight= less CO2 demand.
P stellata is a big weed! It can be very aggressive and yours sounds like it is doing that well. Tonia and Erio's are less agressive and do fine at less light also(1/2 or so what you have is plenty) I've had them all doing well in my 180 in large amounts.

I got rid of them after hacking and pruning so often.

I use a fair amount of GH booster(2 table spoons 2x a week), I use 8000K ADA light, coralife 6700K(I did find some CSL 8800K plant bulbs finally in 35" sizes), dose a lot of Traces, KNO3/PO4 etc.

Tap seems a bit like yours.

So CO2 is more the issue and adding more and/or reducing light are two ways to go about addressing it. None of these plants demand this much light and will grow nicely at 1/2 this amount for years. They will grow faster however at higher light, but the CO2/nutrients also need scaled up appropriately also.

This is why some folks can get away with little dosing, nutrients etc, while others have trouble, it's all about the rate of growth and demand.

More light is not better.

Also, if you use the MH's etc, placing them higher is often better so you do not get the hot spots, rather, and lower, but better area spread can yeild more total growth out of te aquarium than sitting the lights close to the surface, this is true for the more intense T5's as well that pack a lot of light in a narrow strip, and would get better more even spread if they where rasied up another 4-6-8-12 " etc.

My typical ppm's are about 20ppm for NO3, 2-3 ppm for PO4, GH about 3-4 mostly from GH booster, CO2 about 30-40ppm, light varies depending on the tank, goal, location etc. I use ADA aqua soil with nothing but some old sponge mulm added, and dusting or ground peat to start.

I add about 5-10mls per 80 liters 4-6 days a week of traces from 3 different chelator sources. Tropica and SeaChem flourish can be used at these same rates together.

That's about it.
You have a light meter to adjust and see what the PAR is, so you can do that, but measuring the CO2 is much more problematic for most.

Slowly adjusting it and add more slowly, did I say add progressively more CO2, slowly?

Eyeball the tank and health, give things some time, watch fish close, do not add CO2 at night time ever.

Tom Barr