Brown algae

[Mike Lewis]

Hi everyone
I have just tried to revive a pond I have in the garden that I dug years ago when my son was small. It is a kind of kidney shape about 10 feet long and 6 feet max diameter of the larger end. I allowed it to evaporate over lockdown then repaired three holes with patches. Refilled with tap water and all was well for a few days. I have loads of newts and a couple of frogs. I’m the last couple of days I have added new pond plants and now am plagued with what looks like brown floating sludge. I assumed it was some of the soil from the new potted plants and have cleared it completely only to find it returned. Although it looks like patches it is actually individual pieces about pin head size. They all collect in patches and the once beautifully clear water has turned brown. I am a complete amateur and would like to know what this is and if it can be got rid of?
Thanks in anticipation of your advice

 

[Mmathis]

Hello and welcome!

 

[j.w]

@Mike Lewis
Might be just a pond scum of rotting material rising from the bottom? Full of nutrients for plants. You can net it out w/a fine net and dig it around your land plants.

 

[Mike Lewis]

Thanks for that. It looks like minute specks of that tree bark you use for garden mulch. I completely cleared it once but it was back again in the morning! I’ll try again

 

[j.w]

Is there a tree nearby that could be dropping stuff?

 

[Mike Lewis]

Hi JW. Yes, there are trees nearby but I don’t think it’s that. Rather bizarrely, it’s all gone again this morning. I wonder if it’s coming up from the bed of the pond (it’s only about 15 inches deep). I’m intrigued to see if it reappears during the day when the sun is on it. Watch this space thanks again for your advice

 

[Mike Lewis]

Me again. Three hours later (12.30) and whatever it is is returning. Clearly not from trees but rising from the pond itself. Any further ideas anyone?

 

[brokensword]

I think were it me, I'd put in a nice supply of floating pond plants and see if the added competition stops this. I bet it 's some sort of bacteria/algae that is thriving with light and heat. If it's floating and can easily be scooped using a flat pool net, I'd just clear it that way while waiting for the plants to get established.

 

[Mike Lewis]

Thanks for that Brokensword. I’ll give it a go