OK, So I have dosed my pond with a Barley Straw "Natural" Compound . Then I decided to check up on exactly what the risks were on here ! OMG , Now I'm worried I'm thinking its the same as a normal algicide or is it something different and ok ie carries a lower risk ? I followed the instructions, added the correct amount into a bucket of pond water first, evenly added it and have left my 2nd waterfeature going, as its a waterblade and its agitates the water alot. What should I be on the lookout for - danger signs ? How long after adding should I expect the algae to start breaking down and contaminating the water , reducing o2 ? Background: My Pond has had a massive outbreak of stringy algae this week. Every surface is covered and it looks horrible. As I'm having a big BBQ and get together with friends in 4 days time, I needed it fixed fast ! Bring on the quick chemical fixes ! At first I thought it was overfeeding ( as I was away and had a houseguest feeding for the week) but I got him to show me how much was being used, and it was ok. I had also added significant fish numbers (50 inches of koi) 2 weeks before and thought I had a cycling problem. Pond is 1486 gallons, with a 2000 gallon per hour pump and pressure filter. Tested the waters and everything is good on Day 1 of treatment , no detectable levels of Ammonia, Nitrites or Nitrates. PH was 7.5, but after the Barley Straw was added, its now 7.0 I'll measure it again in the morning - perhaps a water change if it drops below 7 ? My pond is all rainwater, so its all soft water, which I think means the PH can lower if you dont clean out the sludge as it forms ? I have one 24/7 waterfall, and I'm thinking this doesn't make enough O2 for the fishies, as they wont go up the other end of the pond, they always stay up the end with the waterfall. I cant leave my waterblade going all the time as its a bit noisy and I don't want to risk upsetting the neighbours, but it certainly mixes up the other end of the pond pretty good. Lastly I'm suspicious about extra sunlight, We have had a good solid 4-5 bright sunny days in a row, spring is very late this year for us, would this be enough to cause a bloom, as my pond gets 80% sun. I'm able to easily perform water changes if fish look like they are in distress and have rainwater on standby to add from the storage tank, but dont want to purge too early.