Well done!
I’ve lost track of this journal and just did a catch up now
300 rummy nose in 2000 litres - should do just fine, especially as auto drip was changing 400-600 litres per day
Depending on which species you had, they may be sensitive to oxygen levels - green water can easily decrease oxygen levels (both as a living bacteria and as a dying bacteria)
I’m dubious of any link between ammonia and your green water outbreak - for me it’s an annual Spring event ... most years it’s just a slight clouding of the water but I’ve also had the pea soup effect - which becomes a concern re oxygen sequestration
I’ve yet to measure any ammonia during the “trigger” season (obviously won’t measure any ammonia during a GW event as any free ammonia will be rapidly consumed)
Ultrafiltration (diatomaceous earth) is one of the most consistent methods for dealing with GW, UV likely comes in second (did nothing to my pea soup)
Large water changes (as in 80-90% not a mere 50%
) are helpful as it physically reduces bacteria level, and oxygenates water (most tap has significant dissolved gases including oxygen and CO2, depending)
Rummy nose can be sensitive to shipping, die off usually begins several days following and may be the odd fish here and there, or catastrophic
Columnaris may definitely be present (again death may be consequential or catastrophic depending on strain) and as this infects gill as a primary site, oxygen lack is again an issue
You can certainly “prepare” your filter for sudden fish increases by feeding heavily for a couple weeks prior, but the more usual method is just to feed new fish sparingly over the first couple weeks, combined with frequent water changes
Buying in smaller (juvenile) fish rather than adult size, generally improves success rate
- fish are definitely young and not aged
- smaller fish usually ship “better” re lower mass and volume for the limited water/oxygen present in the shipping bags
- young fish generally stress less over the crowding and change in environs than adult fish
And of course, they present less of a bioload change when added to aquaria
