Submerged plants dying, insects decreasing

[ManxDave]

I started a wildlife pond in January. By spring there was a good selection of wildlife including diving beetles, fly larvae, red mites but all my submerged plants kept dying ( hornwort, water crowsfoot etc ), the water lily and reeds seem OK. The water is clear, with occasional small amounts of blanket weed which I have removed. Now the only wildlife I can see are pond skaters and water boatmen ( large back swimmers and the smaller lesser water boatmen ), no beetles, mites or larvae.
Three questions, what is killing my submerged plants, why have I very few insect species left and what water test kit do I need?
I did put some hessian sacks ( sandbags ) around the pond edge filled with soil and wildflower seeds which have been a success but could they have been treated with a chemical that is affecting the pond??
Many thanks for any advice, Dave

 

[addy1]

I would not think it would be a issue. Have you tested your water recently? like ph etc.

Welcome to our forum!

 

[Mmathis]

Hello and welcome!

Are there any fish at all? If not, maybe there isn’t enough “fertilizer” in the water. I’m not a bug expert, but is it possible that some of what you had were seasonal-type visitors? I know it tends to be that way with amphibians (frogs, toads, etc.), where they‘re here one day and gone the next. Also, I’m not familiar with what your seasons are like. Right now, August, we are in the middle of summer.

 

[GBBUDD]

Need a whole boat load more info. Size for pump fish location conditions test rests etc

 

[j.w]

@ManxDave

 

[ManxDave]

Thank you for your welcomes and replies.
There are no fish and I wasn't planning to introduce any, I was wanting it a natural 'bug' etc pond.
Yes here in the Isle of Man, British Isles we are mid summer too. They could be seasonal visitors but all the submerged plants have definitely died.
There is a small solar pump to trickle some water down the stones at the back.
You are correct I need to do a load of water tests. I will order a kit and do that before getting back to you.
Thanks Dave

 

[brokensword]

I'd think if your pond has any maturity at all, and therefore organics decaying on the bottom, there'd be enough food for your hornwort. That said, fish go a long way toward providing necessary nutrients. I'd definitely wonder if the sandbags and wildflower mix had any additivies. Was this pond doing well and the decline happen AFTER you did this? I'd check out the 'ingredients' list of the bags to make sure something wasn't added, like fertilizer that might have been too 'hot' for the pond. It would be worth it to get a liquid test kit and test for phosphates and nitrates (the plants like these).

Is it possible some sort of airborn chemical was sprayed and got into your pond? I know around here, they periodically aerial spray for gypsy moth larvae. Just a thought.