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Hey everyone,

Still battling my cyanobacteria problem in my 4ft.
Did the black out, bga disappeared for about a week, but came back again.

I'm suspecting phosphate.
Before I did the black out, I added phosphate removal bag to the filter. When I opened the filter today, I can see the medial bag covered in BGA.
There there, i think we've found our suspect. Phosphate
Obviously the level of phosphate around the media bag is going to be very high, henced covered with BGA even with no light.

The media bag looks kind of yellow now, i suppose it's exhausted from only 2 weeks in water.

Any suggestions?
Keep adding phosphate remover to the filter?
Sorry don't have phosphate test kit, phosphate in tank is high i think it can be concluded, not sure in tap water though.
Well I did some research on local water, the river close to my house is very high in phosphate. And I assume that's my water source.
I'll just ring my water company up and ask them.

There is a product called Sera Phosvec. Anyone heard of it? Is it worth a try or not?

The following is copied from http://www.aquaticlifeaquariums.com.au/

Sera Phosvec
Eliminates Phosphate in Freshwater Aquariums

Sera Phosvec binds disolved phosphate in the water immediatly and lasting. The bound phosphate (visible by the fog formation) is then removed from the water by means of an aquarium filter.

Use 25ml per 100 litres of aquarium water. With phosphate levels below 2mg/l add half the dose mentioned.


Regards,
Jim

Hi Jim,
I just wanted you to know that you are not alone in your
frustration. I too am battling BGA. I too did the black
out for a three or four day period, and cleaned out the
tank, only to have it reappear. GRRRR!

I read various posts, and explored various sites, and
all said to have a Nitrate around 5-10 and NO phosphates.
So, I carefully cleaned, did water changes, and got the
nitrates in hand. Then I read through everything I was
adding to the tank, from fish food to fertilizers for
the plants, and eliminated anything that had phosphate
in it. Still got the BGA ...
I'm about ready to nuke the tank with medication but in
the long run that's not going to do it if I don't resolve
the cause in the first place.

I don't think that product is available here in the States
or I'd try it!
Good luck, and keep us posted!

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

You are barking up the wrong tree with phosphates.

Jim, I doubt the BGA you saw in the filter was alive and growing. BGA is photosynthetic and needs light to survive (that's why the blackout kills it off) it wouldn't be able to survive in a filter. More then likely what you saw was dead BGA that had been sucked up by the filter and trapped in the phosphate removal pillow.

High phosphate in itself is pretty harmless. What does happen though is that phosphate is like a super booster for plants that really drives nutrient uptake. Having high phosphate will increase the usage of other nutrients to the point where they bottom out and all your left with is the phosphate. So you end up in a situation where everything is very low and P is high leading to the assumption that high P is the root of all evil ! When in fact the real issue the low levels of the other nutrients, not the high P. Poor old phosphate has got a bad rap because of this.

You are both in the same both, blackouts worked but it came back , meaning the root cause was not addressed.

Frank you mentioned you got the Nitrates "in hand", that usually means reducing to most folks ?

Do the black out, get and keep the NO3 to 20ppm, just add it , don't trust the test kits, the kit may be telling you you have 5-10 ppm but the BGA is telling you you don't, who you gonna believe? Keep circulation good and the tank oxygenated, and the best way to keep the tank oxygenated is healthy growing plants (which means good levels of N and P).

Forget about phosphate, except to add it !Keep at about 1-2ppm but make sure you keep N at a level about 10 times more then your P to ensure there is enough i.e a P level of 1ppm would need 10ppm of N minimum, 2ppm of P = 20ppm of N.

---

Some days you're the pigeon and some days you're the statue.

Remember that age and treachery will always triumph over youth and ability.

Thank you for both your replies, they are all very very helpful.

Bensaf, the phosphate absorbing media is the very last medium in the flow of water. It's an ehim 2215, media in the order of EheimMech, 2 Blue Foam, Eheim Substrate, Seachem Matrix, and last Phosphate absorbing media. I checked all media, only the posphate absorbing media has phosphate covered. Also, it turned really yellow in just 2 weeks. The BGA covering the phsphate absorbing media is still very fresh and seems to be alive and growing, ie. attached to the media not easily washed off, slimy

I know that phosphate alone is not the cause of BGA. But what else could? If i get rid of most of the phosphate, it would solve the problem right?

I have plenty of amazon swords in the tank, 72watt 6500K 8 hours daily. No carbon dioxide, no fertiliser, NO3 around 10ppm

It puzzles me too to find BGA in the filter, it's really just chloroplast in its original form, shouldn't be able to live without light.

What about high level of organics in the water? Will that cause bga?

Hi Ben & Jim,
Now all I need is a test kit for phosphate that "I" can
use. I purchased one from SeaChem, but have yet to
figure out how to use it (the math stimies me). I know
from earlier experiance and reading that you are correct
Ben, I just need to figure out exactly how much Phosphate
I do have and go from there.

As far as BGA actually growing in the filter is concerned,
you must have light available for that to happen. So far
mine is all confined to the tank itself. It's odd, I have
green, hair algae in the upper 1/4 of the tank, and BGA
in the lower 1/4!

I ought to take a picture of it and post it in the
"Tank from Hell" thread that FP had one time.

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

If i get rid of most of the phosphate, it would solve the problem right?

I very much doubt it. But you don't have to take my word for it, you can prove to yourself one way or the other.

You already have the phosphate pillow done, so if it's working you should have little to no phosphate. Still have BGA ?

As I said, the only way I can see P having in impact is in it's relationship with other nutrients. Low P will drive down N consumption, so may lead to your Nitrate levels rising , thereby hurting the BGA. That too could look like Phosphate = BGA.

It's a subtle difference, Phosphate may not be cause but can effect something else.

Swords are real Nitrate hungry, that combined with good P may be causing N to bottom out. You may have less then 10ppm of N. The test kit is saying 10ppm but the tank is saying something different.

---

Some days you're the pigeon and some days you're the statue.

Remember that age and treachery will always triumph over youth and ability.

The swords are sucking up all the nitrogen availiable in the tank.
My ammonia, nitrite, nitrate readings are all 0ppm.
I'll order a phosphate test kit from seachem.

I doesd some nitrate by adding water from another tank with high nitrate, result is new shoots emerged from a number of swords the following day.


So, I think I can conclude that plants need two major macronutrients, nitrogen and phosphrus. And only when both of them are availiable, the plants can effectively use the macronutrients. Hence, if all nitrate is used up, plants won't take in phosphate, hence we get high phosphate reading. Vice versa, if there is no phosphrus availiable, plants won't take in nitrate, hence we get high nitrate reading.

Is that correct bensaf?

Also level of nitrate should be 10 times level of phosphate.
So my plan is to get a bottle of phosphate fertiliser and nitrogen fertiliser and test kits. Lots of mucking around with chemistry, but I don't really mind. Plenty of calculation to do, but oh well. Some biomedical chemistry can come in handy here.

so ppm 1 mole of substance in 1 million mole of water
c1v1=c2v2

Guess it's different in maintain nitrate and phosphate level in planted and unplanted aquariums. In just fish aquarium you'd want to get level of nitrate and phosphate as long as possible i suppose, but in planted tanks you'll need those nutrients in the water.

Bensaf, in my other tank without any plants, if i had BGA, the only solution is to remove any nitrate and phosphate right?


Cheers,
Jim

just did a quick calculation

assume the level of phosphate in my tank is 0.2 mg/L or 0.2ppm
and the volume of my tank is effectively 200L

hence according to that nitrogen content should be 10 times the content of phosphrus, the concentration of nitrogen should be 2 ppm

c=2 ppm
v=200L

c1v1=c2v2

the total nitrogen in seachem nitrogen fertiliser is 15000ppm.

c=15000 ppm
v=? (trying to find)

c1v1=c2v2
2*200=15000v
v=400/15000
v=26.7ml

I'll need to dose 26.7ml of seachem nitrogen fertiliser to achieve the level aimed.

Does it sound legitimate?

The swords are sucking up all the nitrogen availiable in the tank.

Is this where I say I told you so

My ammonia, nitrite, nitrate readings are all 0ppm.

There's your BGA problem right there !
I must admit it's unusual in a non Co2 tank to have this situation, BUT with a light fish load and hunry big plants like swords (they represent a huge plant bio-mass) it's very possible.

I doesd some nitrate by adding water from another tank with high nitrate, result is new shoots emerged from a number of swords the following day.

There you go, the tank and plants pretty much tell you everything.

So, I think I can conclude that plants need two major macronutrients, nitrogen and phosphrus. And only when both of them are availiable, the plants can effectively use the macronutrients. Hence, if all nitrate is used up, plants won't take in phosphate, hence we get high phosphate reading. Vice versa, if there is no phosphrus availiable, plants won't take in nitrate, hence we get high nitrate reading.

Is that correct bensaf?

Pretty much. Plants need all nutrients available all the time. The lack of one pretty much stops the uptake of all others.
Phosphorous is a little different in that it pushes the uptake of others especially nitrate. Potassium is the same. Magnesium and calcium can effect one another also.
Generally it's not a major issue once you ensure you have sufficient amounts of everything.

You lost me on the calculations but one thing to be aware of - the N ratio is just a guide. Yes mathematically 0.2ppm of Phosphate = 2ppm of Nitrate. But 2ppm of N is nowhere near enough. Keep at 10-20ppm N. Really the ratio is just to bear in mind that if increasing P , N should be increased also. But the same would be true if increasing light, Co2 etc.Anyway to my mind 0.2ppm is a little low - I usually shoot for 1.5-2ppm.

In a non planted tank , assuming that N is at a decent level, BGA is usually a lighting/circulation/oxygen issue.
Keeping the light low, flowing well and bringing in oxygen(planted tanks have vastly higher levels of oxygen compared to non planted tanks) will keep it at bay. Oxygen can be added by keeping the surface moving or by airstones. Personally I hate airstones and prefer to keep the surface rippling gently.

---

Some days you're the pigeon and some days you're the statue.

Remember that age and treachery will always triumph over youth and ability.