Fish and Aquatic Plant Pond Problems: Sometimes We Don't know the Answer (Hence the Solution)

I got this email form a reader and I couldn't provide a specific answer.

Tony - THANK YOU for the book !

As you said in your advertisement ... I was NOT disappointed.

I've been a pond gardener since 1991 - my Wife and I.

I just set up our newest pond this past couple months and this year was the FIRST time that I purchased a UVC ( with YOUR help ) and yesterday ... Day 2 ... our water is clearer to the point that we CAN tell a difference because we can see the bottom !

I am sure that within a few more days we'll have crystal clear HEALTHY water.

Question for you:

No other change to the pond, contents or whatever ... after placing the new UVC on the bottom.

*****

Without boring you with all the details of pump size, wattage, arc length, water flow, type of bio filter I am using, pipe restrictions, etc, etc, etc ....

I have noticed an immediate change in my lilies and water hyacinths - their leaves are yellow today ( Day 2 ) after having started using the UVC.

This seems totally cooincidental from my readings in your book ( I read the entire book in 2 evenings and took copious notes ) as the UVC should only be killing living cell organizisms - right ?

Even if the flow would be too slow and the dwell time would border on sterilization as the PondMaster 20w submersible ( there are some details for you ) stated ... I am guessing the leaves are turning yellow due to the lack of something like nitrogen, like leaves on a corn stalk.

However nitrogen is a chemicl, not a living organizism - I believe.

And if this is the case than the UVC can't be elimanating nitrogen from my water plants.

Okay, so perhaps the UVC kills some bacteria - that shouldn't have robbed the plants of any "green" food should it have ?

I need some direction here and perhaps a suggestion of what I can add to the water ?? to beef back up my leave color without contributing to the algae growth or anything of course which would be harmful to my few fish and bio filter.

*****

My fish ?

900 gallon pond, 9 feet across and 24 inches deep ( plastic livestock water tub ) sunk 1 foot into the ground and surrounded with rocks.

Full sunlight with a pergola being built around and over it ( to help shade and hold black pond netting to prevent the herons from killing my fish ) that should be finished by the end of next week.

2 Golden Orfes

2 Blue Channel Catfish ( presently half the size of any other fish )

2 koi

NOT overstocked - ha !!

I will mention that a few weeks ago when learning about Baking Soda to act as a buffer for Kh and Ph, I spinkled it in the pond and the wind carried it over my plants.

When I came home that day those plants were all but DEAD with the leaves all turned BLACK and curling with crisp white edges by the following evening - yikes !

I saw that you suggested limestone?? chips in a media bag to do the same thing.

I then later found where you had recommended marble or shells.

Marble and shells are not available to me.

Limestone in a small bag I can do.

Also I did not find anywhere to PURCHASE a pound or two of the wonderful ALFAGROG that you and a zillion others go on about ??

Oh, if you'd like to see any photos of my pond(s) without plugging up your email, I've put a little web site together as I continue to construct this year's pond.

I need to get more pictures of this year's pond up there after the pergola because I just took a quick look and saw that I only have a couple up of this year's pond and they are pretty sad - very early in the build process.

Thanks for any input as you have time Tony - razor

My Unsatisfactory Answer..

Ray, Hi and thanks for the email

I am sure that the UVC has nothing to do with the yellowing of your plants leaves.

Indeed yellowing of plant material can suggest lack of nutirients (especially iron even in trace quantities.)

However one thing puzzles me ... is your UV actually submerged in the pond?

If so it's conceivable, but I'm guessing, that if the UV source is very close to the plant material it could have an impact. If the UV is outside the pond then definitely not.

The effective radiating power is lost within inches from the UV source.

If you can find a suitable one use a very specific aquatic fertiliser which would be very slow release.

In general however it is not a good idea to add fertiliser. So only do this if you confirm problem is lack of nutrients and use in very small quantities

There is no correlation at all between UV and nitrogen levels nor bacteria levels in a pond.

I would cut off yellow leaves and see what happens ... if problems persist then I suggest you talk to an aquatics plant specialist

As a general rule it is a bad idea to add anything to a pond unless it is a natural product consistent with what happens in the natural environment (eg Viresco) ... maybe you are seeing the results of the baking powder addition.

Making 20% water changes each week for the next 10 weeks or might also help to rejuvenate your plants.

No harm at all in using a bag of limestone chips ... just make sure it is good quality and washed beforehand in pond water. Tony