I have been having some issues with burnt tips on acros and pale to chalky montis for the past 3 months. The challenge was every wc (Once a week 10%) as soon as the water change was complete half the acros in the tank tips would melt, but the next day all the montis would look better. so by the end of the week the montis would be worse and the acros would recover. A little history... Tank is about 10 years old. 90 dt, BB 20 gal sump about 85 total valume Curve 7 skimmer danner 900gph return (2) maxspect 250 gyre running at 90% (1) hydor 1150 powerhead 1/4 hp chiller tunze ato Mechanical dosing BRS 2 part feeding pe mysis, rods and lrs Fish stock Sailfin tang, powder brown tang, (2) anthias (3) chromis a royal gramma clown and a malerius wrasse. Mainly sps,acros and montis. Some lps favia acans and a duncan. Salinity 1.025 temp 78 alk 2.5 meq/ 7dkh i know its low but its stable cal 430 mag 1385 po4 0.1 no3 10 all salifert test, refractor for salinity ROdi unit from spectra pure ~ 0 TDS and 0 for chlorine i also supply a buddy with water and he has no issues. Tank maintence wc once a week 10-15 gal, blow rocks out once a month, suck out ditritus with wc. change sock weekly ( never overflows) salt was fritz but i had some concerns it was the cause, so last week i switched and am now using aqua forest. After bang my head against the wall, i employed triton for a test to see what is really in my water. the results are in and the concerns are ... B~ 11mg/l P~ 181 ug/l p04~ 0.5538 My concern is the Boron. Where it is possibly coming from and how to get rid of it. After posting in Randys reef chemistry section i guess the boron isn't really a big deal. If there is anything im missing pleaes point it out or ask me anything to find a solution to this issue. At this point im scared to do a wc and tomorrow is wc day. Fwiw heres the complete result from triton.