Too much water changing

[VitalApparatus]

My tank is 16 months old.For the last 5 months Ive been doing weekly water changes.The fish and corals really seem to come alive after each one.
However I do think Im changing too much water out too often.
My tank is 75g with a 55g sump filled about 75% of the way,thats about 100-110 gallons total volume.
Ive been using two rubbermaid roughneck 32gal trash cans for mixing new and dumping old water.
I would say most water changes are about 15 gallons RODI H2O(judging by how much salt it takes to reach 1.025) a week.
Perhaps this is too much every week and is contributing to cyano growth in the tank.
Any input is appreciated. :bounce2:

[Sk8r]

You're fine. Cyano happens. Poke the blue number under my avatar and read the entry under Algae: it's got a bit on how to get rid of cyano and keep rid of it.

[MrTuskfish]

IMO, changing 15% of your water weekly is way beyond what most folks do. 20-25% monthly may be a ballpark figure for "normal", unless you have a massive bio-load or water quality problems; which may be the case. WCs should not contribute to cyno problems. Can you check water params before a change and post them? A 15% WC really doesn't seem like enough to have a big effect on fish & corals; but its possible.

[Mad_Reefer]

I do less. Much less. I have watched cyano disappear without water changes. It's all about nutrient control and water movement.

[RenoR1]

I do 16 gallons (Half that 32 bucket) every two weeks on my 80 with the exact same tank volume as you.

[Bones06]

Perhaps this is too much every week and is contributing to cyano growth in the tank.

From what I have read, water changes should reduce the amount of stray nutrients in the tank therefore reducing the cyano. I would look at the quality of water coming out of the RODI and make sure that it is all 0's. Hope this helps :)

[chathomas]

I do 20 % every week with a little larger tank then you and everything is thriving. I may try to decrease to every 2 weeks but why stop what is working?

[James404]

15% water change a week is a great way of nutrient export. I do roughly the same amount religiously every week, no problems with cyano yet. I would try to increase flow in those areas as well as keep your nutrient levels as low as possible by means of wet skimming, GFO and Carbon etc.

[stingythingy45]

Water changes all depend on the bio-load,coral species and what type of mechanical filtration you have.I've gone months with no water change with only a few sps brown some as a result.

[steelhead77]

IMO, water changes are never a bad thing for a tank. Look at the oceans and lagoons where these creatures live, there is always water being imported and exported. They rarely live in stagnant water.

[lloydkeller]

on my 120 I do do 10 gal a week I can get sea water at 1.10 a gallon