50% water change

[tram]

In my effort to reduce nitrates in my system I plan to do a 50% water change using Red Sea coral pro salt. I am aware that I should prepare it at same salinity & temperature but is there anything else I should worry about. Current specs are
SG=1.024 pH=8.1 No3=16 Po4=0.012 Alk=8.6 Ca=420
RSR425xl (425litres)

I have 2 small acans & 3 lps frags
1 small lobo & goni frag

Thanks
Tony

 

[ndrwater]

Make sure to check the ALK in the new water made with RSCP. In my experience, it tends to mix up higher than your current parameters. An ALK swing is potentially much more dangerous than high nitrates.
And... For what it's worth, 16 Nitrates isn't something I would be alarmed by at all.

 

[Dr. Reef]

i agree. i normally keep nitrates at about 10 ppm and somedays they creep up to 15. its not something i would change 50% water for. Alk swing is something to watch for when doing such large water changes. Salinity temp pH and Alk should be monitored and matched.

 

[pdxmonkeyboy]

I have suffered sps losses from doing a large water change and having alk rocket up. I am almost certain the RSCP salt is going to mix higher than your existing alk.

you can lower it by adding acid.. I believe muratic acid. and then letting it circulate to get the ph back up.

research what acid to use however, my memory is not what it used to be.
:(

 

[biophilia]

Muriatic acid is correct -- though it's extremely caustic and will bring the pH of the new saltwater down fairly dramatically until it's aerated. I've used it on many occasions to bring RSCP salt down to ~8.5DKH (it mixes at 12+DKH). Mishandling it can result in serious injury though... much more trouble than it's worth IMO. Just go with regular Red Sea blue bucket salt if you want something that mixes up at ~8.0-8.5 DKH

Also, 16ppm NO3 is totally fine if you're not trying to run an ultra low nutrient tank. I intentionally dose nitrate to keep my NO3 at 15ppm.