Egg String Spawn & Mites ID Please

[dogstarheaven]

sorry folks, but i don't have any pix for you, but will try and get some done for tomorrow.

yesterday, i put in some tadpoles from a community garden into my pond as my frogs from last yr didn't make it over the cold winter and hence there were no spawn in the pond. today, in amongst the plants, i found a whiteish string of about 3cm long and 5mm wide. the opaque white eggs are lined in the centre but in alternating left and right fashion (does that make sense?? i can't describe it really, sorry!). it's attached to a watermint and is quite near the surface of the water. i'm not sure whether this was already there or it came with the tadpoles..

the other query i have is a load of mid-brown v small mites (they have lots of small legs and scurry v fast!) and some have come out on the edge of the pond moving around.. i'm quite worried about these as i don't wish to have these potentially causing a problem to the pondlife i have, or worse still, that they might be mozzies...

can someone help?
thanks in advance