So what I did which worked is I have four jars all one gallon. Two for Tisbe cultures in active use and one for phyto in active use and one for storage in my Fridge. When I want to reset my phyto I just take the one jar that is empty and pour some of the culture into that jar for use in my tanks. I then add newly mixed saltwater to the original jar and then add more F2 fertilizer to get it going again.
I keep the existing jar empty for harvesting of the cultures.
The reason it crashed the first time is I had a culture that was working but when I started it originally I did it with a mixed group of phyto which I heard is not the best way to do it. I bought a strain from Top shelf aquatics but it was likely over a month old and it crashed immediately. If I just used my original batch it would have probably been fine.
There is a couple of different strains of phyto but it seems Nannochloropsis is the best one for me as people say it is the easiest to cultivate and it eats waste and then can be skimmed out. Corals, Pods, eat it as well.
People do say you need to do a full reset of the culture every 3-4 months bleaching or peroxide cleaning the original container and then adding some of the original culture back to the original container with fresh saltwater. Its vital to use RODI water though when cleaning it as you want to prevent bacteria from getting in the culture. Some people fully reset the culture every time they harvest but that would make it way too difficult. I have heard of some people never resetting the culture with success as well.
