# Algae issues using Estimative Index dosing



## jrflanagan (Jul 4, 2010)

I’ve been using the EI method for dosing dry ferts for a couple months now, and have developed some serious algae issues – both blue-green slime algae and green dust algae. They are coating the entire tank. 
I realize that algae issues are a matter of something being out of balance, but I’d like some suggestion on what I should try adjusting and in what order. 

Here’s my setup:
210 gallon tank (72x24x29)
2 FX5 filters
Pressurized CO2 - ~30 ppm

It's a densely planted tank, but the plants are not very mature yet...so I would not yet consider it a heavily planted tank. 

*Lighting:*
8x 39W T5HO
3x 250W MH

For the first month I only ran the T5HO. On for three hours then an hour break. On for a total of 9 hours/day. I ran the same lighting for 6 months before I started the ferts and CO2 with no algae issues. 

At about 1 month I started turning the MH on thinking that maybe the light was the thing out of balance. I only have them on for 45 minutes/day (one light at a time) due to the heat they generate. I did not see any improvement in the algae, but it didn’t get any worse either. In fact, the plants seem to love it. The amount of oxygen bubbles coming off the plants when the halides are on is tremendous. 

*Fertilizer:*
I’ve been dosing with the following regimen:

Su, Tu, Th - 2 tsp K2SO4 (Potassium Sulfate), 1 tsp KH2PO4 (Mono Potassium Phosphate)
Mu, We, Fr - 1 tsp Plantex, 1/8 tsp Iron Chelate
Sa - 50% water change

I do not dose KNO3 because my nitrates are consistently at 30ppm+ thanks to the fish. 

I’ve read about how, when in balance, an over abundance of phosphate will not contribute to an algae issue by itself. I believe the EI recommended amount of KH2PO4 leads to 14.75ppm of phosphates….with the recommended level being 1-3ppm. Does that high of a phosphate level really not cause any problems?

So what do you think I should try adjusting? Too much light? Not enough light? Dial back the ferts? Could CO2 be contributing?
Any suggestions would be greatly appreciated.


----------



## nazrm (Mar 22, 2011)

How is your flow? Deadspots? How do you know you have 30ppm of CO2? (dropchecker?) Using an external reactor or something else? Misting?

Way too much light with the MHs. Pearling is just a response to the light, not an indicator of happy plants. I'd use maybe 6 of the T5'd until you've got algae issues under control. (quite possibly a CO2 issue ime) 7-8hours a day.

Also I don't trust test kits, so I think you should add KNO3 regardless. Doesn't hurt, and if it has no effect you can just stop dosing.


----------



## DarkCobra (Jun 22, 2004)

+1 to all of Nazrm's suggestions.

As for the nitrate issue, it will help to consider this. What _forms of nitrates_ are your fish producing? Potassium nitrate? Sodium nitrate? Calcium nitrate? Just to name a few among dozens of possibilities.

Are all of these different forms equally useful to plants? Equally easy to efficiently and quickly metabolize in a fast-paced, high light environment, where plants require lots of nutrients?

The tests don't distinguish between different forms, they just report total levels. Wouldn't the least preferred forms be the ones that build up the most, leading to a test result that's misleading as to the actual amount of nutrient readily available to plants?

That is why it's possible to see adequate, or even huge excesses of nitrate in a heavily stocked tank, with a test kit that is functioning perfectly; yet still have deficient plants, and consequently algae problems. The same goes for phosphate.

So ignore the tests. Dose KNO3 and KH2PO4 as recommended. I regularly see phosphate levels similar to yours and even higher nitrates in my own tanks. Reducing my dosing to try to "compensate" gave me nothing but trouble until I figured this stuff out.


----------



## plantbrain (Dec 15, 2003)

Calibrate the test kit 1st, before doing ANYTHING or making any management decisions.

Algae are typically from too much light, too little CO2 or not enough nutrients.
Seems like you have all 3 going for you.

None of this has anything to do with the dosing method.


----------



## xmas_one (Feb 5, 2010)

That's a boat load of light, I'd try killing the mh's for a month or two until the tank really fills in proper.


----------



## youjettisonme (Dec 24, 2010)

re: MH

I have been running MH since my tanks inception, but I've always kept it raised quite a bit above the substrate so I don't think that my PAR levels are likely all that high even with my 150 watts of MH. Am I off base in thinking that raising a really strong light is equivalent to changing those lights out for weaker lights? Even if someone was using T5HO and not MH, would raising the T5HO give you the same net result as turning off bulbs?


----------



## Sharkfood (May 2, 2010)

I've had GDA grow quickly when my CO2 was too high, and BGA likes low oxygen. My guess is maybe it's a gas or gas exchange issue.

I also get GDA anytime I leave for a week or two and my tank doesn't get dosed often, if at all. The prevailing theory is that GDA likes low phosphates, though I've never done a real test on it. When my tank doesn't get dosed, phosphates are low, but then again, so is everything else.


----------



## plantbrain (Dec 15, 2003)

youjettisonme said:


> re: MH
> 
> I have been running MH since my tanks inception, but I've always kept it raised quite a bit above the substrate so I don't think that my PAR levels are likely all that high even with my 150 watts of MH. Am I off base in thinking that raising a really strong light is equivalent to changing those lights out for weaker lights? Even if someone was using T5HO and not MH, would raising the T5HO give you the same net result as turning off bulbs?


This is why you use a light meter or speak to someone that has one, uses one etc. It's VERY rare to have too little light using T5's.

Come to think of it, I've not seen a case yet

So.........folks rattle on and on over waste, water changes, ppm's of this or that, but few bother to address the elephant in the room, light and measuring, testing that aspect.

CO2 is the other biggie.

Dosing is very easy then.


----------



## plantbrain (Dec 15, 2003)

Sharkfood said:


> I've had GDA grow quickly when my CO2 was too high, and BGA likes low oxygen. My guess is maybe it's a gas or gas exchange issue.
> 
> I also get GDA anytime I leave for a week or two and my tank doesn't get dosed often, if at all. The prevailing theory is that GDA likes low phosphates, though I've never done a real test on it. When my tank doesn't get dosed, phosphates are low, but then again, so is everything else.


I've not looked, but I had high PO4 is the one tank I managed to get and keep it for more than 2 weeks.

All the other of the 5 tanks had the same dosing/water changes/light PAR(Spectrum was likely different, I have doubts this is an issue, and am not going to get into that). A CO2 showed a dramatic difference in the CO2, once corrected, the GDA never came back and I have been unable to induce it even with inoculum from other folks.

PO4 we can test for fairly easily and KNOW, CO2?
This is far more troublesome for many, light spectra? Same thing.
Given everything I've seen, CO2 is the more likely candidate, but this can be said for many algae. 

The CO2 was still what one might think as adequate and good, but the other tanks that could not get it or inoculated had about 20ppm higher CO2 consistently(40-50ppm vs 20-30 ppm).


----------



## jrflanagan (Jul 4, 2010)

hey everyone.

sorry it's been a couple days since I've been able to respond to all of your advice. 

I think my gas exchange is good, and I don't believe I have any deadspots. 

I'll try cutting back on the light...and I'm going to try and find a light meter that I can borrow from someone. 

I'm going to play around with the CO2, and dosing KNO3 as well. 

I've read that the best method of getting rid of green dust algae is letting it grow until it dies out......should I just leave what's already there and just watch to see if the new growth diminishes as I make adjustments?

Thank you for all of the advice.


----------



## MarkMc (Apr 27, 2007)

youjettisonme said:


> re: MH
> 
> I have been running MH since my tanks inception, but I've always kept it raised quite a bit above the substrate so I don't think that my PAR levels are likely all that high even with my 150 watts of MH. Am I off base in thinking that raising a really strong light is equivalent to changing those lights out for weaker lights? Even if someone was using T5HO and not MH, would raising the T5HO give you the same net result as turning off bulbs?


Yes, increasing distance from the light source lowers the intensity of the light. If raising the fixture is not feasible then you can use window screen to reduce it.


----------



## efface (Aug 27, 2010)

I had Catalina Aquarium make mine and I had the reflector reversed to the non-polished side. Don't have a PAR reading but you guys think this is still strong light? running 2 T5 bulbs over a 40B with legs.


----------



## MarkMc (Apr 27, 2007)

I have my fixture a foot higher than yours. 2 T5 54 watts over a 55 gallon.


----------

