On Sun, 29 Aug 2010 07:58:20 EDT, Phyllis and Jim wrote:

Not only our WH, but also our water celery is yellowing in the new
growth. Iron? I doubt it is a nitrogen issue with koi and goldfish
in the pond. Lilies seem to be doing fine.

Any thoughts on what is going on or how to check.

I'd go for iron and get some iron sulphate, available from garden
centres in the uk. You only need a tiny amount, something like 12grams
per 600 gallons. The water is likely to go hazy for a day or two but
will clear eventually.

If you have a lot of plants they could be using up all of the nitrates
so it's worth getting a test kit for that and checking.

--
Regards - Rodney Pont
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