Bubbs

My 2.5ft tank is suffering from a major algae problem. I have brown sludge forming between the glass and the gravel and over some of my plants and some fuzzy stuff on the chain swords. There is also some green spot algae on the anubias which I think is quite normal as they are slow growers but noticed some of the anubias leaves are getting black algae that is as tough as green spot algae to remove.

Here are some specs on my tank,
Size: approx. 120litres. NO c02
Lighting: 2 x T8 fluroesent tubes 18 watt each (1x plant grow tube and 1 x normal daylight tube cool white)
Substrate: Plain gravel 2-3mm size with clay balls under heavy root feeders
Ferts: Every 3rd day Potassium, Flourish Excel. Once a week - Flourish. At water changes - Iron
Water changes of 40-50% every 2 weeks through gravel vac.
Nitrate: less than 10mg/l
kh: 7
gh: 8
ph: 8
Tank load: 6 Rainbows, 1 bristlenose and 1 blue ram (fed twice a day)
PLants: Hygros, blue stricta, several anubias nana and afzellii, java ferns, crypts, vals and chain sword which has stop sending out runners.
My tank has been running for over half a year now and algae issues started a few months back. This is my first planted tank and I thought brown sludge or diatom occured in new setups? e.g the first couple of months. I'm abit lost as to what I'm doing wrong or what is out of balance. Can anyone give me some advice on how to correct the problem?

Carissa1

Since you're already adding potassium and evidently have nitrate readings, maybe you are missing phosphate.

HeyPK

Does your tank contain snails? What kind or kinds? Has the snail population declined recently? When I get algae that sounds like what you have---brown sludge and fuzz, especially soft fuzz that snails ought to be able to eat, I find that my snail population has declined and that the reason for the decline is not enough iron. Try increasing your iron additions by three or four times. If I am right, your snails should make a come-back and clean up the algae in a few weeks.

Bubbs

Hi
thanks for the replies, I don't have any snails in the tank only fish.
Could it be excess iron rather than lack? Maybe leaching from the substrate?

Carissa1

I would put my bet on some kind of deficiency. Especially considering that you are getting more than one type of algae. It's hard to get too much of something to hurt your plants, but it's easy to get not enough, especially if you're not dosing all your micros and macros. As soon as your plants become deficient in something they are weakened and algae starts setting in.

Bubbs

I think ur right. There probably is a deficiency beacuse the chain sword and vals have stop sending out runners for the last few months. The question now is which one???
There isn't any obvious signs of deficiency except the older leaf of an affzellii tip is turning slightly yellow other than that theres nothing else all other plants are growing well.
Should I increase the dose of all ferts??

Endler Guy

If your tank is over six months old, you may need to change the light bulbs. They tend to weaken about that time. The lower light output makes a better place for diatoms, especially at a little over 1 wpg or 3.33 watts per liter. Even if your lighting hasn't weakened, it might not be enough for the plants but enough for the algae to come in and take hold. Since you have some nitrates, yet aren't adding any, I'd assume that you aren't lacking in other nutrients. You will have more phosphates than nitrates from fish food alone. So, if you have any nitrates, you should have about twice the amount of phosphorous. (Diana's book pg. 80)

Since you are using excel, you may want increase your lighting and try Tom Barrs EI dosing regimen for non-CO2 tanks. He doesn't recommend water changes but rather to take a break in dosing in order to purge excess nutrients. He has a different opinion on allelopathy and iron limitation for algae control but he defends Diana's methods because he's tried them and they work. He won't hesitate to tell that to naysayers either. http://www.barrreport.com/articles/4...2-methods.html. Look toward the bottom for recommend dosing for excel dosed tanks.

If I were you though, I'd upgrade the lighting to at least 2-3 wpg or 36-54 watts total. Using excel makes carbon less of a growth-limiting factor for the plants.

Carissa1

Isn't Excel poisonous to vals?

Good point about the lighting too, I didn't catch that.

Bubbs

Thanks for the link it was an interesting read! I think light is probably one of the issues but I also think I might have a nitrogen deficiency and excess phosphates. After testing for nitrates yesterday I found that nitrate readings have droped to 5mg/l, this was tested prior to a partial waterchange. Noramally I wouldn't do waterchange if the nirates are at a good level but the sight of build up of mulm in the tank was too great to bare. I assume that the hygros are responsible for the drop in nitrates as they are the latest additions. I'm just wondering if this is a good thing that nitrates are dropping? Or a sign of worst things to come?

Endler Guy

It can be. I've used it and killed anacharis with it. I was so excited when I found out about excel because I thought plants needed some kind of carbon fertilization. Now I know that I can see them grow and do fine without. I did see in the Seachem forum that plants can be acclimated to it slowly.

You must be American if you didn't catch that about the lighting. I learned metric conversion in high school but it's left me from non-use. I used a converter to get his wpg. That's pretty sad, isn't it?