Blue Green Outbreak

[jmuccillo]

Has anyone had any luck completely elliminating blue green algae from their tank after an outbreak.

I have had a heavily planted tank set up for around 2 years. It was running perfectly fine for at least 18 months with no significant algae problems and then a few months ago I had a blue green algae outbreak. It was a moderately aggressive outbreak and covered the java moss, java fern and ambulia in my tank reappearing fairly quickly after each clean. Not entirely sure what triggered it. I suspected it could have been some nutrients in the tap water because I noticed similar outbreaks in display tanks at two LFS's around the same time.

In any case I went through a process of reading up on the subject, increasing frequency of water changes, measuring nutrients, particularly Nitrates and adding a phosphate spounge to my external canister filter. The problem now appears to have receded to a point where I only need to clean away excess algae once a fortnight and then it only covers a few plants in the tank. However, I don't seem to be able to completely elliminate it.

I would prefer not to use antibiotics as I have heard they can affect the biological filter. I have heard UV sterilizers can get rid of the problem but am not sure about long term use of such a device in a planted tank. Anyone have any suggestions.

joe2

 

[George Farmer]

Hi joe and welcome.

In my experience BGA is caused by a combination of factors; dead spots in the substrate and water column, LOW nitrates and too much natural light, in particular reaching the substrate behind the front glass to name a few.

Have you heard of black outs? These work well in most instances. Completely block your tank out from all light for three whole days - no peeking!

I've had success with Maracyn (antibiotic). My BGA started in the substrate and was visible behind the front glass. I simply broke up a few tablets and inserted them into the infected areas. It cleared up in no time. Now I regularly insert a credit card between the glass and substrate just to stir up any problem build-up of detritus etc. that may lead to another breakout.

If you have good plant growth and low nitrates then it may be worth adding KNO3 if you don't already. Aim to keep nitrates at 10-20ppm and phosphates around 1-2ppm. This goes against old-school thinking in that NO3 and PO4 lead to algae, it is now commonly accepted that a lack of these nutrients lead to algae and possibly BGA.

What is your filter flow like. Most planted hobbyists prefer a low turnover to prevent CO2 loss but this can lead to the dead spots as mentioned. Personally I like a fair bit of flow, it distributes the nutrients effectively, prevents dead spots and any CO2 loss is compensated for by my pressurized CO2 - after all, CO2 gas is cheap, BGA is not (in time and stress etc!)

 

[houndour]

The only way I got rid was antibiotics.

You could try a blackout. This worked for me but only for about a week. Try a 3 day blackout. Complete seal the tank with binliners. Absolutely no peeking. Turn of CO2. And dont forget to turn off the lights!

Some causes of bga are stagnant water and low nitrates.

Zig advised me to add nitrates just before doing the blackout. The blackout is very effective. But you need to address the cause for it to stay away completely. And if even the tiniest bit remains after the blackout, it will return.

you beat me to it, George!

 

[jmuccillo]

Thanks for your prompt replies,

In fact before the main outbreak I had noticed algae between the glass and substrate so there was perhaps some underlying cause. After the outbreak I measured nitrate levels and they did not register on my Hagen test kit. Following this I started adding potassium nitrate taking the nitrate levels up to around 5ppm. I haven't been measuring phosphate levels so can't tell you whether they are too high or too low. I suspected they may have been too high at least before the addition of the phosphate spounge due to the improvements I got shortly after its addition. I doubt they would be too low due to the fish load in the tank and the amount of dry food I use.

I use a canister fileter with outflow around 4 x tank volume (1000 l/h in a 250l tank). However I do aim the spreader jets towards the glass to minimise disturbance within the tank.

I'll also give the blackout a go and let you know if I have any success. I asssume three days of complete darkness won't harm the plants.

Joe.

 

[zig]

If you want to try a blackout

Remove as much of the bga as possible and then clean your filter

Do a 50% water change and add 10ppm nitrate to the tank

Switch off co2 if you have that running on your setup

After the 3 day blackout is over do another 50% water change and add a further 10ppm nitrate to the tank

A 3 day blackout will not effect your plants or your fish they will be fine.

 

[jmuccillo]

Hope you don't mind me asking but I don't quite understand why you would add nitrate before the blackout. I imagine the plants will not be able to use the nitrate with the lights off. Won't this create an excess of nutrients in the water that nothing can really use.

joe2.

 

[iggy01]

Hope you don't mind me asking but I don't quite understand why you would add nitrate before the blackout. I imagine the plants will not be able to use the nitrate with the lights off. Won't this create an excess of nutrients in the water that nothing can really use.

joe2.

Plants still grow at night. You may find they are a bit leggy after the blackout.

You have been given some excellent advice IMO.

Good luck!

 

[Sime]

Everyone above has said it all realy Joe, its an ugly thing to look at too I admit!

It wold be worth getting some maracyn in stock too as when I did a blackout for the same reason it was fine for a week to ten days, then it started creeping back. A good dose of Maracyn put stop to it and I haven't had any since.

Simon

 

[George Farmer]

I don't completely understand the science behind adding NO3 - all I know is that BGA can out-compete the plants for nitrogen so I guess adding NO3, even before a blackout, helps win the battle in the plant's favour.

 

[jmuccillo]

Thanks for all the advice. It all sounds good to me.
I'll give the blackout a try first and see how it goes. If the bga comes back then perhaps I'll need to give plan B a try.

On the subject of maracyn is it fairly easy to source? I live in Australia and don't really know where best to look for it. It may not even go by that name here. Also will it effect the biological filtration. Should I perhaps look at moving some of the fish out of the tank to reduce the bio load during treatment.

Merry Christmas to you all,

joe

 

[jmuccillo]

I thought I'd keep you posted on progress with my bga outbreak.

Its now been a little over 2 weeks since I completed a 3 day blackout and right now I am feeling very optimistic. The bga has by and large disappeared. A small amount did appear between front glass and gravel after the first week but I used the credit card trick to keep it at bay (probably the best use I’ve put the credit card to for some time). After the second week even this small amount appears to have receded to the extent that I cannot find any in the tank. Touch wood it won't return anytime soon.

It wasn’t just the blackout however. I took your advice on a number of issues and made fundamental changes to the way I fertilize, increased CO2 as well as increasing water movement within the tank to address dead spots. I am still fiddling with these parameters as I learn more about the methods you advocate but the results suggest I am on the right track.

Plant growth in the last 2 weeks has been exceptional. All this extra growth and I have not had to invest in any new equipment. In fact the tank is looking very much overgrown at the moment and I can see myself having to spend more time pruning to keep things under control. Oh well… that’s a small price to pay for a sparkling algae free tank.

I’d like to thank you all for the very good advice received in this post. Having a tank which is once again relatively algae free makes this hobby a lot more fun.

 

[George Farmer]

Having a tank which is once again relatively algae free makes this hobby a lot more fun.

You said it.

Glad it's working out for you.