I've got very hard water, dose fertilisers like theres no tomorrow and stock lightly so not a great comparison for Nathan but I'm not noticing any loss of GH and all water readings are very stable. I'm doing about one 20% waterchange every month or two and top ups at least once a week. My tank is supporting a lot of terrestrial growth so that probably helps:
I'm not sure its advisable but its definitely possible to keep a stable tank without a lot of water changes.
You're preaching to the choir. I wouldn't have put fish in at all given that no one knows anything about ponds or has any interest in maintaining one! The goldies look like comets and have done ok over the winter. There are more goldfish than coy but I've only done a quick headcount, I didn't take note of how many there were of each.
I have gotten enough money from HR to buy some dechlorinator, a full test kit and a few other bits to help us clean the pond. Its still far from ideal but things are looking up at least.
Ok I count about 16 fish (mostly small). I will admit to knowing nothing about sterlets but the 'sterlet sticks' here are also wheatgerm based so I'm rather confused now. Presumably there are different breeds of sterlet?
I did nitrite and ammonia tests this morning and both were surprisingly good. 0 nitrite and .25 ammonia which shouldn't be too toxic as I've added a load of ammolock (post test). Hopefully once the extra filter media arrives the water quality will clear up. That only leaves issue of inappropriate stocking.
It is horribly overstocked but I can't really fix that so for now I'm just trying to mitigate the problems as best I can. I hope I can stop any more fish going in there but since the fish buyer is a lot higher in the company than me there is a limit to how far I can push this right now.
I don't have any photos but I would guestimate the pond is about 2.5m long x 0.5m deep x 0.75 meters at the widest point of the crescent. The filter is clearly undersized but both filter and power supply are concreted in so getting an additional filter will not be trivial. I haven't counted the number of fish but even not accounting for growth it is still ridiculously overstocked. The sterlet alone is about 30cm and presumably just a juvenile.
You may have noticed that Ive been a bit quiet recently. I have a new job keeping me busy! Unfortunately the office has a little courtyard with a pond which has been given the the apprentices to look after. Neither of them know anything about fishkeeping and every time theres another spate of deaths one of the directors just throws in a new batch.
I think I can stabilize it a bit just by doing proper maintenance and putting more media in the filter but I have a few questions:
Is an all in one pond food pellet ok for a mixture of coy and goldfish? It seems to be mostly wheatgerm and spirulina.
There is a large sterlet in there and it doesn't even try to compete for food. There is a lot of algae but would I be right to put in some veg for it as I do for my plecs?
Are there any plants that may help mitigate the overstocking issues but not be eaten by the carp/goldfish?
Its kind of hard to guess whats wrong when there are no specific symptoms. Have you noticed any stunting, yellowing, brown spots, pinholes etc?
Just general slow growth in my tank usually means Ive let the floating plants take over and there isn't enough light, the bulbs need changing or I've under dosed nitrates again. Could you give your most recent test results? Maybe something will jump out.