Really confused with amount of dosing in large (650 gallon) new system

[djkms]

So almost 3 months ago I setup a 600 gallon aquarium with about a 100 gallon sump. With rock displacement I would say its roughly 650 gallons total.

I have very few corals in the system (not enough to even make a dent with consumption in my opinion). All the rock is "Marco" type rock and the sand is basically "Marco" sand.

I am literally having to dose roughly 1500ml per day of 2-Part to break even which is roughly 3.2dKh and 22ppm CA. That just seems crazy high to me.

I am dosing into the overflow chamber of the sump right before the socks

I have also tried dosing the CA at night and Soda Ash/Sodium Hydroxide during the day - makes no difference.

I dont really see precipitation anywhere except around stagnate water lines in the corner of the tank and sump. The sand in the tank is not getting hard

I am dosing sodium hydroxide to keep the PH up and then switching to soda ash when the PH is over 8.3

Is the rock just consuming all this? Not sure where it is all going. Never experienced this before. However I have never had a system this big and all my previous systems used live rock and very little marco rock. I do understand consumption will be higher with such a high water volume but this is crazy for such a new tank. In my previous 210 fully stocked SPS tank it was only consuming 2.5dkh daily, roughly.

This recent photo shows over 2k ml for dKh as I am trying to raise the alk up to 8ish and it just seems the more I increase the more it consumes.

Any help appreciated, thanks.

 

[gbroadbridge]

What happens if you don't dose anything?

 

[djkms]

What happens if you don't dose anything?

I haven't completely stopped in about a month since I have corals in there now but when I did it would drop about 1.5dKh (can't recall on the CA) in a day. At one point I let it get about 5.5dKH before taking action to bring it back up again.

 

[djkms]

Well I moved my dosing lines to my return chamber next to my return pump. I also put a powerhead in that area to create turbulence. Hopefully this solves it. i thought the overflow chamber for my drain lines was turbulent enough but maybe not? I doubt the socks are removing it because they don't get caked up when I change them out. I just didn't want to place the lines near a pump because it will just require more cleaning for the pump but it is what it is. Hopefully this fixes it...never dealt with this before but I cant think of anything else other than its precipitating out...

 

[gbroadbridge]

Well I moved my dosing lines to my return chamber next to my return pump. I also put a powerhead in that area to create turbulence. Hopefully this solves it. i thought the overflow chamber for my drain lines was turbulent enough but maybe not? I doubt the socks are removing it because they don't get caked up when I change them out. I just didn't want to place the lines near a pump because it will just require more cleaning for the pump but it is what it is. Hopefully this fixes it...never dealt with this before but I cant think of anything else other than its precipitating out...

If it were, I'd expect it to be pretty visible given the amount you are adding.

How much Soda Ash are you adding per 1000ml of RODI?

 

[djkms]

If it were, I'd expect it to be pretty visible given the amount you are adding.

How much Soda Ash are you adding per 1000ml of RODI?

355 grams per gallon measured on a food scale for soda ash
and
283 grams per gallon per the instructions here for the sodium hydroxide.

 

[djkms]

So I stopped dosing everything at 4pm yesterday:
Alkalinity 6.51
Calcium 426
Magnesium 1346

4pm today:
Alkalinity 5.17
Calcium 401
Magnesium 1351

I also removed all the stony corals since they weren't happy anyways. Still seems like an excessive drop in 24 hours for natural processes.

 

[piranhaman00]

Yes that is not correct. Alk of 5 is not really possible either.

 

[djkms]

Yes that is not correct. Alk of 5 is not really possible either.

That's the reading on my Trident and I checked it against my Hanna checker which reads 5.7. My checker has consistently read .5 higher then my Trident.

Possible or not that's what it's reading. Curious to see my results tomorrow.

I'm dumbfounded with this....