water changes?
 

what is the best way to change water in my 200 gallon tank i have a sump in the bottom. mix water and salt in a bucket and pour it in the top or in the sump, im not sure what the best way is.i also have a siphon that hooks up to the tap but again mixing the salt is my problem....thanks

I would pour the mixed water into the sump where the water from your tank enters. That way it has time to mix with the tank water and keeps the temp more consistant.

water changes
 

wouldnt it overflow the sump?

If you are doing a water change you are taking out water as well as putting in water. If you were just adding water yes it would overflow, but since you are taking out the same amount of water as you are putting in it will not overflow. When I do water changes I take out 1 bucket of water then add in a bucket of water and so on till I've changed the amount of water needed. My sump is only a 33g, so if I were to take out to much water before adding new water my sump pump would end up running dry.

This is what i do
 

I have a very small sump!

Since I can’t just take a bucket of water out without the water level dropping to close to my return pump

What I do is have a tube coming out of my main tank siphoning into an empty bucket during my water changes

and as that is happening, I have a fresh bucket of pre mixed saltwater next to my sump and I just add cups full in till the exchange is done.

i just turn my system off and use an internal pump in my sump to suck water out then put that same pump into my mixing bin and pump that in as i turn the return pump back on

If you sump is that small, what happens during a power outage? Would the sump overflow? What I do is shut off the return pump, the sump fill but doesn't over flow. Then I remove a bucket of water out and pump the FSW into the sump using a MJ400. when I'm done I turn the return pump back on.
Just make sure your sump won't overflow during a power outage!!!!!!

When I do water changes I siphon mostly from the display and only about 40l from the basement sump and fuge but do know the total amount I'm taking out.

When I'm ready to start adding the water back, I just turn on the return pump to fill the display back up and start adding the known amount of water back to the sump. If it's looking like the sump wouldn't hold all the water, I'll just shut off the transfer pump, and if it looks like the return pump will start to run dry, I'll just shut it off until the transfer pump catches up.

I turn off my system as well. When I turn it off, a few gallons syphon back into the sump. To do my water change I syphon water from the main tank. Then turn my system back on so that it pumps some water back up to the main tank. When the sump water is low enough, I turn off the system again. The sump now has less water and I add new mixed water to it and let it warm up before turning my system on.

I shut down, siphon 15g or so, and dump new water into display. This causes everything to get stirred up, then when I turn system back on, the suspended detritus goes down to the filter sock in sump.