Also while we’re on this fish topic. I upgraded my UV for my 115g tank from 15watt to 25watt AquaUV
I’m running 300gph on the pump.
Is that too much for parasites? I would believe it’s uw or EOL rating is 100k-110k
90k is rated @ 400gph
Depends on what you are trying to kill with that dose. Cryptocaryon has a very high kill rate requirement, and as a side stream application, will just not control active infections. Noga et-all maintain that UV, in a tank-to-tank application, UV can stop downstream infections, but in a side stream, as used in home aquariums, the dwell time is always too high, and some tomites/theronts get through. Here is a write-up I did on this:
UV sterilizers
Ultraviolet (UV) sterilizers are also sold as a “cure” for Cryptocaryon. The problem is that most hobbyist-sized UV sterilizers do not have the power to make an effective kill on the relatively large Cryptocaryon parasite. Additionally, UV sterilizers are effective only on the tomite/theront stage, as this is the only point where the parasite is even present in the water column.
The fallacy here is that tomites/theronts must leave the fish. Actually, some of them get caught up in the fish’s mucus and stay attached until they become infective trophonts again. This means that UV sterilization will not eliminate active Cryptocaryon infections from a single aquarium. Where it does have benefit is in eliminating tomites as they pass through a filtration system from one discrete tank to another (like in a public aquarium or fisheries lab). Decades ago, diatom filters were touted as cures for ich and velvet. The same issue applies with them; there are adherent forms of these protozoans that can continue to infect the fish without ever having to leave the fish’s body. Even if they do, the “dwell time” factor means that some theronts will still be present in the water column to infect the fish.
A recent study (Ge-Ling, 2022) indicates that the UV dose required to kill Cryptocaryon theronts/tomites is 185,000 uw/S/cm2. They do go on however, to conclude: “ …both ozone and UV are ineffective in controlling infection within an individual aquarium because of the adhesive nature of C. irritans tomonts (Ma et al., 2017). Therefore, the focus on UV and ozone treatment should prevent live theronts flow into aquaculture ponds. Second, the tomonts are strongly resistant to UV or ozone than theronts, implying that recommended production doses cannot wholly kill tomonts….”
Jay
