cyano question

Can cyano kill zoas? Never had a large bloom but just some in places, but all zoas look bad losing polyps. All parameters ok just don't understand whats going on. The cyano has been vacumed out of sand

 

Cyanobacteria does not kill zoanthids but Dinoflagellates do. I suppose if the matting of cyano was so bad and left in place it could do damage.

Another option may be zoanthids eating nudibranchs or perhaps sun dial snails.

If you could post a picture of your zoanthids that would really help.

 

As mentioned the cyano will not cause the harm unless it blankets the coral – I suspect it would be too coincidental to be a cyano bloom *and* a coral munching Nudi. With that in mind I would say that whatever is feeding the Cyano bacteria bloom is also having a negative impact on your corals. Most often you can’t test for it until a day or two after you clean up the bacteria – this is because its being consumed by the bloom.

Failing skimmer quite often leaves excessive DOC’s in the system, check there. Nitrates due to the usual causes – CO2 build up from low flow due to a faulty pump perhaps.

It’s all the same old story – in my opinion identify and rectify the cyano cause and you will more than likely resolve the coral issue as well.