Q+A - Cyanobacteria, algae problem

Help I'm plagued with Cyanobacteria, I have a Fluval Venezia 190, I have a fluval 405 filter running with h2ocean nutri-fix NP 120 ml, fluval biomix & ehiem bio mech, together with a TMC Vectron 200, V2 ozone (lowest setting every three hours) & a hydor slimskim nano 135-35. Two hydor koralia 2200 circulation pumps,

I have 1 aquaray reef blue running from 10:30 until 22:00 and two, 2 foot T5 marine white's running. Soon to be replaced by 3 aqua ray LED lighting 1 reef blue, 1 marine white & 1 Fiji blue.

I've tried easy-life's excital twice, but I can't get rid of it. I'm doing a 25 litre water change using R O water every week. I siphon as much out every water change as I can. I sure this stuff would survive a nuclear war :(.

Dear Jason

First of all my friend I know how you feel! Over the last decade I have established over 100 maintenance contracts and believe you me, every single one of those tanks is an individual. No single aquarium acts the same as another; there are too many variables. However we can look at the main contributing factors when a problem arises.

Cyanobacteria is very difficult to sort out, there is a reason why this is one of the most successful micro-organisms on earth. Notwithstanding it is present in most aquariums but can be kept under control relatively easily, it is in cases like yours when it takes over that the problem can become overwhelming. Briefly touching on your statement ‘I’m sure this stuff would survive a nucear war’ – it was one of the first things to come back after the Chernobyl disaster!

When one of my maintenance staff mentions they have an aquarium with a persistent algae problem I will first perform a site visit and ask the following questions:

1) How long is your light on for?

You have answered this for me already. 10:30 until 22:00 – this rings alarm bells for me, I always tell my clients, ‘the more light the more algae’. It is very rare that you will see any of my aquariums with the lights on for more than 9 hours a day. In private home installations where the lights do not necessarily need to be on for public display purposes I incorporate a siesta period. So the lights come on for 4 hours and then ramp down to 50% or sometimes 0% (off) for an hour and then ramp back on. This is a technique used to ‘confuse’ the algae.
I would suggest that if you have a fish only system then you would have next to no light while you were dealing with this problem. If you have a reef tank then you need to adjust your lights to the absolute minimum without having a detrimental effect on the corals. This is something that will need to be implemented over 6 – 8 weeks while you are trying to sort the issue out. When the algae calms down you need to seriously reassess how long your lights are on for.

2) Have we tested the water?

As part of my maintenance contract we regularly test the water, a diary is kept of every aquariums individual water quality results. I can then look at the book and see if we have had a spike in the NPK ratio.

Phosphorus (I look at phosphate)

These are the main nutrients that algae feeds on. Unfortunately your water quality results would be more useful for me than an equipment list, for instance you should test for these parameters as a first port of call when an algae problem arises. The more NPK present the more the algae can grow. There are many products on the market that will soak up phosphate, get on the forum and ask your fellow fish keepers what they have tried and found successful.

I think your problem can be sorted with some aquarium ‘lifestyle’ changes. I wish you all the best of luck.

Happy Fishkeeping.