How long does it take!

[dindi]

I have had my SW tanks (75 and 20 gal) 2 years now. I still have off and on problems with diatoms and cyno bactria. WHAT do I need to do? My water parameters are as follows:
PH 8.4 in both tanks. temp 76 in 20 and 80 in 75
ca 420 in 75 and 450 in 20, SI are zero in both, PO4 is .001 in 20 and .010 in 75. No trites and trates the same at .02 in both tanks, no am. Alks are 9 in20 and 10 in75. I don't over feed and do a water change of 10% using RO/Di water weekly. I use Instant Ocean. I am using my 20 gal for corals (none yet) I hsve a problem with cyno in the 20 and brown algea (diatom) in my 75. can anyone give advice

 

[ocellaris_keeper]

Either your using TAP water or your RO/DI filter unit needs replacement filters.
also make sure you are doing a 1% water change weekly.
Problem solved

 

[reef fool]

How old are your bulbs? PC bulbs should be changed every 9 months or so. Quality of light can lead to bad algae types.

 

[dindi]

Bulbs are new less than 3 months as for my water..never used tap water maybe my LS store needs to change? well her filters have a red or green light for changes, it was always green when I bought the water. Now what

 

[reef fool]

Just a thought.
Maybe double check your PO4, nitrate and silicate tests at the LFS to make sure your kits are reading the same as theirs.

 

[ocellaris_keeper]

well I am not going to say your LS is the problem - but I don't trust and LS within 60 miles of my house.
You can get an RO/DI filter on ---- for about $150.00 for 75 Gal per day - that's what I did and it has been worth every penny.
the only other answer would be a better protien skimmer - typically diatom bloom and cynao bac. are due to nutrients in the tank
Only three ways to have too many nutrients:
Over feeding
nutrient rich water
Insufficient skimming

 

[dindi]

Well my LFS is up on all whats going on. I trust her(should I not) Always very honest and lets me know if (a fish or frag won't work.) Now in my 20 gal I am using the seaclone skimmer.It hasn't picked up anything for at least 2 months. Just runs clean. Don't use one in my 75 gal because it is running a "merical mud system" my skimmer never picked up jack s...t with this filter. please help