Blue Green Algae

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carfey

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Nov 27, 2002
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I set up a new planted tank a few months ago and I've gone through streaks of different algaes but now I'm all of a sudden having a real problem with blue green algae. It only grows on the gravel and I vacuumed it up just yesterday to see it back worse today! I've cut back fertilizing in the hopes it would fix it but it's only gotten worse.

My water is 5' KH, pH 7.0, so my CO2 is about 15 ppm (DIY injection). I have 1.45 watts per gallon left on for 11 hours a day. I change 25% weekly and I have a fairly light fish load (3 corys, 4 otos, and 3 blue gouramis). I used to fertilize twice a week with Flourish and Flourish Iron like the bottle says but I cut back to just at water changes and even less than that now but with no luck. Ammonia, nitrite and nitrate are in check. I can't afford to get a phosphate test kit right now but I'm not convinced it's very high. Anyone who's had luck eliminating BG algae please help!

PS - I'm specifically looking for remedies that don't involve antibiotics.
 
Pick off all you can, trim the plants etc, do a 50% water change, add KNO3 at 1/4 teaspoon per 20-30 gallons of tank water(not volume) right afterwards.

Remove the CO2 for the time being.

Now turn the light off and cover the tank up so that no light at all gets in for 3 days. Use towles/trash bags etc.

After 3 days is up, do a 50% water change, add the same amount of KNO3 back. Add the CO2 back.
Keep up on adding the KNO3, traces, and you might consider getting some PO4. Try down at the drug store for a fleet enema, it's most liquid PO4.
Add 1-2 drops per 20 gal, 2x a week.
That should take care of most of it. Make sure the pH is in the 6.8 to 6.9 range especially at night before the lights go off.

The 3 day blackout is very effective at ridding a tank of BGA.
Keeping gone is up to you. Grow the plants well and it will not come back.

Regards,
Tom Barr
 
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BGA problems

I'm battling BGA and searched to find this thread. I have a couple of questions as to whether this will work for me. I have tried the 3 day black out twice, and the BGA keeps coming back. I did not dose with KN03 during the blackout routine. I am dosing lightly with PMDD (premade from PlantGuild), but I think I'm not dosing enough yet.

1) Is there a connection between pH and BGA? Why does Tom recommend keeping the pH 6.8 to 6.9? I ask because I'm keeping Apistos in the tank and I'm using CO2 to push the pH down a bit (to about 6.2).

2) The tank is 75 gal, about 2 WPG. Planted with a fair amount of bolbitis and a ton of crypts. The bolbitis is doing well, but the crypts havn't established themselves well yet. They are hanging in there, but are not thriving yet. QUESTION: Will the crypts pull the nutrients from the water column, or should I be looking at substrate fertilizer?

3) I'm using Profile. I'm thinking about supplementing with clay pellets w/ fert. If I go the clay pellet route, should I make them with PMDD or should I be using something else for the crypts? I have picked up the components for PMDD to mix my own.

4) Will the KN03 dosing hurt my Apistos (A. Bitaeniata)? They're new fish for me, but I have been led to believe that they are somewhat sensitive about water quality.

THANKS!
 
It's almost gone!!

Just an update on my BGA problem! I did a 75% water change about a week ago and syphoned off as much of it as I could. The next day it was back worse than ever. I did a 20% change two days later and once again vacuumed up as much as I could. It came back fiercely once again.

Several days later, I did my usual weekly 25% water change and added fertilizer like usual. It is almost a week later and there is very little BGA present! There are bits left but I think I'll be fine from now on.
 
BGA lives on next to nothing.
Plants need a good deal of NO3, K, po4, Traces etc.
Adding that will increase the plant's growth which in turn means the plants will produce O2.

Blackout is very effective but it does nothing if you do not correct the reason why you got the algae in the first place.
All a blackout does is kill wimpy little algae.

It will not make your plants "grow".

pH is only relevant to the associated KH of the tap/tank water.

See www.sfbaaps.com under pH/KH/CO2 table.

Measure your KH, then see what pH you need for 20-30ppm of CO2 in the solution.
Add enough CO2 gas ONLY to do this.

If you feel a pressing need to have soft water, do not drop your KH below 3 generally or the GH ever.

Then you can hit the pH in the 6.2-6.4 range with good CO2 levels.

For a KH of 5, pH of 6.7-6.9 is good.

You need to measure both the pH and the KH to conclude anything.

The substrate profile has all it needs for plant roots. It's a bit light weight to my personal liking but nice in color. Adding nutrients to the substrate such as iron rich clay will make no differences.

Adding more PMDD or adding pure KNO3 only would be better.
Folks that get BGA tend to have zero reading of NO3.
Plants are starved.

Starving then further will not make algae go away.
You might be alright for awhile, but unless you focus on growing the plants, algae comes back time after time.

You likely have added more food or something that has helped the tank.

Crypts, quite contrary to popular belief and dogma, do extremely well with no substrate fertilizer at all. Some iron rich substrate that is porous is about all a plant needs for improved growth with the substrate.

Folks seem to think that more fertilizer is better.
Consistently added macro nutrients will help a plant to grow well, CO2 being among those and the NPK (NO3, PO4 and K+).

Plants will take it in where it's easiest, the leaves. _If_ nothing is in the water column, they will try and use their roots to find enough "Food".
But they do best with a good rich sub with good water column nutrient levels.

The water column can be easily dosed every 2-3 days like feeding your fish.
It will produce better results than cramming a bunch of junk in the substrate that provide enough nutrients for months/years only to have it burp up when you do a trim or pruning.

And as far as crypt and sword plants go, I know crypts very well in emmersed and submersed culture having flowered a number(15) of species. Sword plants get out of hand and quickly become "Weeds" or "Trees" except for the smallest species.

I'm telling ya, these plants do super with no sub amendments beside iron or profile/flourite onyx sand and perhaps a little peat and regular organic mulm from the tank.

I've been at this for many years and have seen no evidence in my tanks or others to support the notion that plants such as Crypts and swords do any better in rich substrates.

Regards,
Tom Barr
 
Tom,
Thanks for the info. I have seen your assertions that crypts do fine w/o substrate fert before, but being somewhat of a beginner at this, I'm cautious. I agree with your take on possible problems with substrate fert. When I uproot plants, that stuff has to go somewhere (i.e. an instant unintended megadose into the water column). OK, I'll try dosing with KN03 and blacking out again, then I'll increase the PMDD. Again, thanks for the info!
 
You can see a number of my Crypts on line at various sites such www.sfbaaps.com (see gallery) if you have question to the ways of the methods of crypts/swords being big root feeders or preferring one over the other.
The 90 gallon has no laterite/flourite etc, just plain sand.

Basically I cannot keep most swords since after 6 months they get "tree like". For very large tanks, swords are okay. But even a 135 gallon tank gets consumed by a Red Rubin and 1/3 to 1/2 the tank is one single plant 6-12 months. Many swords grow out along the ditches on both coast in the USA. They are wetland weeds.
Small ones like chain swords are fine.


____________

I think overcleaning a filter does not cause BGA. Low nutrients or not cleaning your filter might though.
I'd refrain from getting the filter too clean or washing the bio section off too much. Just get the dirt off.

Poor plant growth will cause many algae to appear.
Strong plant growth will not.

You can kill the algae but you will still need to grow the plants.

Regards,
Tom Barr
 
more questions

OK, still having problems. Tom, I'll admit that have have not followed your cure exactly, but I think my approach has been close enough that it should work. I have cleaned the tank and filter carefully, dosed it well with PMDD, blacked out the tank for three days, then cleaned the tank and kept the dosing level up. The plant growth looks good for slow growing plants (lots of crypts, bolbitis and some wisteria), but my Nitrate levels are still undetectable. I'm reluctant to dose really heavily because I'm keeping some fish that are supposed to be a little sensitive.
My problem? BGA in the substrate, real bad!. I'm using Profile from an old tank. Possible problems are

1) The substrate dried out before I reused it, so benificial bacteria needed to regrow, but the new tank has been set up for 5 months now. That would seem to be enough time?
2) I did not wash the profile before reuse and I thought the organic matter in it would be benificial.
3) Something else?

Help! Anybody have any ideas?
75 gal tank, Profile substrate
110 W CF + 80 W T12s
injected CO2
pH ~ 6.6 - 6.8
gH < 3 deg
 
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