100% WC after cycle

[Liron Mishal]

Hi there.
Cycle is completed about a month ago and now i'm going over everything and making sure its ready for the first batch of fish (currently in QT).
everything looks good, brown algae is building up, Ammonia and Nitrite reads 0 but nitrates reads 80.
as I will be adding some corals is the near future (76 days to be exact), I need to to a big WC.
I do not want to do it in batches and prefer to do a 100% WC. the problem is that I dont have a mixing tank that is large enough.
can i drain all the water out of the DT, fill it up with RODI water and then add salt?
I think it will hurt the nitrifying bacteria but not sure

L

 

[P-Dub]

Some will die, some will survive. Mixing vats are easy. Home Depot sells them relatively cheap. Rubbermaid trash cans. Never can have too many of them around just in case...

 

[Billldg]

So far as I know the bacteria lives in the sand, rocks, and glass, but not in the water column. Questions is why do you want to do a 100 percent water change, I would think that could cause your tank to go thru a mini cycle. 25 percent water change will do just fine.

 

[Idoc]

Use Brute trash cans as your mixing containers. Each holds about 25-30 gallons. You don't have any live stock yet, so you can do it in pieces. Drain about 75% of the tank water (which will expose your live rock to air probably) and quickly replace with premade new saltwater. Hopefully this first batch will be enough to cover the live rock. Then make another batch of saltwater and add it. You are really only under a time constraint to cover the live rock with a new tank.

It's not good to add salt to fresh rodi water that first put in the actual tank.

 

[Liron Mishal]

thanks for taking the time to help.
@P-Dub I dont live in the states, so both Home depot and Rubbermaid are not available
I can get other containers, its the space that makes it difficult.
I do have a 70 liters trash can, so I guess it will have to do.

@Billldg the purpose of 100% WC is to get the nitrate down from 80 ppm after the cycle was done.
I prefer a one time operation and be done with it over a several WCs in few weeks.

 

[Jase4224]

I’m thinking first off that putting fresh water in a cycled tank then allowing salt to then mix is going to very efficiently destroy the vast majority of bacteria therefore defeating the purpose of cycling in the first place.

Secondly if you have high nitrates and no livestock then you really need a way of lowering your nitrate levels. You shouldn’t need to do a big water change to lower nitrate.

What method of lowering nitrate do you currently run?