Water changes: what is too much?

Pisquini · Mar 27, 2012

Hi guys,

Have a funny question again.

I have a 150 gallon hope to be Reef Tank that is about 9 months old. My sump and Refuigm (never spell that right) is filled to about 15 gallons.

I have setup my Skimmer (runs 24hrs a day) to drain waste out of my system and have a float triggered selonoid valve that adds RO/DI water into my sump. This is all automatic off my Apex Neptune controller.

I have calculated that in a 24 hr period I average a 5-7 gallon water change. Which means that in a months time I am changing 150-210 gallons.

All my stats are perfect on my tank. I add salt and other stuff as needed to keep tank stats right.

I was doing 30 gallon water changes monthly. My last 30 gallon water change has been over 2 months ago. I was curious if the system would hold it with out the water changes.

So with all this said, is that too much water changed a month?
Is it safe with my setup to not do monthly water changes?
Am I missing anything as far as thinking I am good without monthly changes if all my stats stay cool?

Thanks in advance for your time.

Decalf · Mar 27, 2012

'I have setup my Skimmer (runs 24hrs a day) to drain waste out of my system and have a float triggered selonoid valve that adds RO/DI water into my sump. This is all automatic off my Apex Neptune controller.

I have calculated that in a 24 hr period I average a 5-7 gallon water change. Which means that in a months time I am changing 150-210 gallons.'

I'm not getting this. How does adding Ro/DI water to top off evaporation = a water change unless your saying that your skimmer puts out 7 gallons of water a day and then you may need to familuarize yourself on skimmers.

Mike&Terry · Mar 27, 2012

There are many trace elements in salt that a healthy reef requires besides calcium, magnesium and alkalinity that we do not routinely test for. The easiest way to keep the balance is thru regular water changes. Your system is relatively new and consumption is probably low at this point. That will change as you start adding corals, how many you add, and the rate at which they grow.

Are you saying that your evaporation rate is 5-7 gallons per day? That doesn't sound unreasonable and has nothing to do with water changes as the purpose of topping of with RO/DI is to keep salinity in check.

erikjphillips · Mar 27, 2012

Your adding Salt to the tank? if your ATO is replenshing evap the should be no fluctuation in salinity. maybe i'm reading this wrong......

Pisquini · Mar 27, 2012

Ok think I am understandiong what you are saying.

I very rarely have to add any salt to the tank. I do check for Salinity, cal, mag, amn, nitrite, nitrate, ph, alk and phos. every 2 weeks. All been fine in the 2 months of no 30 gallon water change.

So what I am gathering is the skimmer is not taking out as much water out as I am thinking, it is mostly evaporation. So I am really not changing the water at all, or at least not as much as I am thinking.

So I should keep up with my monthly water changes too! Right?