Hidy folks. I've been poring over some of the info in this forum, and decided to register, in hopes of hearing some thoughts on my predicament with my black moors in my horse trough pond.

The trough is 330 gallons. I have had it here for 3 years. The trough holds two water lilies, I replace water hyacinth each year. There has never been any filtration system on this pond. First year I picked up three fancy goldfish. The only one to survive the Louisville winter was the black moor. The following Spring I picked up another two. They took to breeding and the trough is presently overcrowded with three Springs' worth of their breeding efforts.

I am aware that I need to thin the numbers of fish. I am addressing this issue.

Some of the fish have had a sort of milky film on them, which I understand to be the result of overproduction of slime coat due to poor water quality, fluctuation in pH or perhaps parasites. I have been doing about a 10 percent water change daily or every other day for the last two weeks. Actually I have been running the hose at the bottom of the trough for a specified amount of time (timing the amount of time it takes to fill a 5 gallon bucket, mulitplying it by 7), as recommended by my local pond shop. My local pond shop said that with such a small change it would not be necessary to treat the water with a dechlorinator, though I have been anyways. I took my water in for a test, ammonia, nitrate and nitrite were fine they said. I did not know about testing for kH. Tested pH here (I have the kit with the drops) in the evening it registered 9, in the morning it registered 7.6. Tested the pH of the tap water, it also registers 9.

The water is green, but no stringy algae. I figure I'll pick up more plants in an effort to cover more of the surface...coverage at present is only about 30%.

Over the last week, I have pulled 5 dead fish. Today's losses (3) included one of the big ones :(.

Questions:

1. I would guess that fish population (a few big moors and something like 30 small ones) has much to do with what is going on in the pond. But....besides thinning the numbers, where do I go from here? The scenario has always been a success, without the filter and with many plants.

2. Does this sound like a pH or alkalinity issue? Of course I must test for alkalinity (I'm headed to the store for a kit upon finishing this post), but does a thick slime coat and subsequent die-off result from pH and kH swings?

3. The pond shop mentioned putting in some salt. I have read so many posts regarding salt, and it seems that the general consensus is don't use it. I am concerned for the aquatic plants.

4. Baking soda: use it?

5. Water changes: continue? More? Less? Should I vacuum out the bottom of the trough, even though ammonia tested out fine?

I hesitate to trust the advice received from the pond shop, based on the general no-salt sentiment I've gathered on so many koi and water gardening websites.

Thank you all for your time.

Mardi