Looking for some imput please.

[MeggyPuff26]

I have some issues going on with my tank, but the corals and fish all seem to be doing fine and showing now bad signs.

My tank is 75g and is 7 years old. I just got my new maxspect Razor r420r 10k 160w LED light for it on Friday,13 along with a maxima clam and a few other corals to add to the corals I already have in the tank. I acclimated everything for an 1hr and 30min. Once added the clam stuck its foot to the rock under the sand within the hour and the corals all opened around that time to.

I just did a water test and I was scared :(
Calcium - 520ppm
Carbonate Hardness - 17 KH
Phosphate - 2.0
Nitrate - 100

My test kit is the API one for reefs, brand new.

I did a 5g water change when I saw the above and tested an hour later with these results:

Calcium - 480ppm
Carbonate Hardness - 13KH
Phosphate - 2.0
Nitrates - 100

We did have our yellow tang disappear or die and got eaten about 2 to 3 weeks ago but we never found the body. My SG is about 1.025 - 1.026. all the corals are looking good and opened, the clam is opening it's mantle to just alittle past it's shell and responds very well to movement above the light, either by moving a hand over it or when a fish swims over.

ANy idea on what I can do to lower some of these numbers? Thanks

[Dmorty217]

A larger water change will drop phosphates and nitrates and alk some more.

[MeggyPuff26]

So should I do another 5g water change?

[MeggyPuff26]

If I do another 5 g water change will that affect anything in my tank so soon after the first one?

[Nina51]

in a 75g, you could easily do a 10g w/c. my tank is 75g and i normally do an 8-9g water change every 10 days or so. there have been times when i was rearranging corals and ended up siphoning more water out that lead to probably a 15g change by the time i was done!

[MeggyPuff26]

So it wouldn't hurt to do another 5 g change after the first one? I do 5g ones because of the buckets I use for my changes.

[Dmorty217]

I was thinking like 30g but that probably overkill. Your alk will fluctuate a lot depending on the salt you use and how long you let the salt mix for. Reef crystals for instance has a high alk to begin with and will vary from box to box sometimes. You could do 100% water change if you really wanted to, it won't hurt anything. I know 2 different people who do 100% water changes on their coral tanks once every 3 months

[MeggyPuff26]

I use Red Sea Coral Pro Salt.

[julie180]

I wonder about your test kits. Wouldn't a clam be showing stress with nitrates and phosphates that high?

I would double check your numbers.

[Dmorty217]

I wonder about your test kits. Wouldn't a clam be showing stress with nitrates and phosphates that high?

I would double check your numbers.

Nitrates yes, possibly. I have a buddy with a 375g Sps tank and his phosphates were off the charts (1-1.5ppm) with no ill effects from the high phosphates so it's possible. He has since started using pool phosphate remover of some variety and it has dropped the PO4 to .03

[MondoBongo]

I wonder about your test kits. Wouldn't a clam be showing stress with nitrates and phosphates that high?

I would double check your numbers.

not really.

due to my own negligence, this past summer my nitrates got way up there. over 80ppm before i finally realized what was going on.

i lost a few of my more delicate SPS, but most of the stuff in my tank didn't look outwardly stressed, they just all stopped calcifying. still had polyp extension on my surviving SPS, my LPS were still inflated, clams still looked normal, but no one was creating new skeleton.

to the OP, in my 75 gallon i typically change 20 - 30 gallons a week as my water change schedule. so you're not going to hurt anything by doing larger changes, as long as parameters are close. most important being salinity, temp, alk.