I have a TMC 60 l reef set-up with LPS, mushrooms and polyps. It has a nano skimmer and the supplied lighting. It houses one Gobiodon okinawae, a hermit and a Peppermint shrimp and contains live rock. It was set up in January but over the last month I’ve been getting slime algae on the rocks and substrate. I syphon it off but it comes back in a day or two. I use Rowaphos and carbon and RO water, bought ready salted from my local store. I only use fresh RO for top-ups. The tank has the supplied powerhead, but would adding another be beneficial to increase circulation? I feed a small amount every day and occasionally add live copepods or brine shrimp. Any ideas?
P. W. ROSE, LINCS.
Slime ‘algae’ (usually cyanobacteria) is invariably caused by high nutrients — with nitrate and phosphate being key factors to look at. Limit these and you can solve the problem. You should be looking at less than 0.03ppm phosphate and 5ppm nitrate or less. Both of these parameters, or a combination of them, is likely to be the issue.
Look at how to limit nutrient input to the system. See if you can cut back on feeding, even slightly. Then, embark on a programme of exporting nutrients. This will include increasing the frequency of water changes (it’s worth checking your salt water and RO water parameters, too), coupled with continued syphoning of the slime — keep up with this. Clean your mechanical filter media on a daily basis to remove detritus (and perhaps look to increase the efficiency of mechanical filtration through the use of additional fine floss or foam). If you’re getting phosphate above 0.03ppm, change the Rowaphos or review how it’s used, as it may need repositioning to ensure it’s working at maximum efficiency. Check the skimmer is
operating efficiently by cleaning and adjusting it accordingly.
Increasing water movement is a good idea, as it will help to remove dead spots, assisting with physically dislodging the cyano as well as the detritus which may settle out and act as food for it, allowing both to be taken through the mechanical filter. In fact increasing water movement is often all that’s needed to solve the problem.