question on RO-Di and water change:

skrivan · 05/08/2015, 11:57 AM

hi. sorry to add yet another water change thread, but I have no-where else to turn. 200 gallon DT with 75 gallon sump and here is my situation:
I have a SPectra-Pure 90 Ro-DI which I use to make fresh water for water changes and also for an ATO reservoir. It's great, BUT, I just yesterday noticed that the DI chamber shows incredibly high TSD (over 135!) so I changed that filter. I had changed the filters (all) previously about 1 month ago, so I assumed I was good for awhile. I found a few corals, (a leather is mainly my concern) not opening up. I also checked all params and everything looks great except for very high calcium. I found that our water in Salt Lake City is super high in calcium (I tested tank calcium at 600 ppm). So, my ATO has been likely putting in water with high TSD and also the last 40 gallon water change I did was with high TSD water. Finally here is the question: should I do a very large water change, like 50% and do it every few days so I can minimize the TSD's I have in there? And, is it possible that the high calcium and TSD are a cause for come corals shutting down?
Thanks.....joe

coralsnaked · 05/08/2015, 12:15 PM

You need to check the TDS coming out of the RO membrane or the last DI canister on the RODI.system. Get an inline meter off the internet for $30 if you don't have one. No need to check for TDS in the DT as that's where all your livestock poo and excess food waste is.

Sk8r · 05/08/2015, 12:44 PM

This is where asking the chemists might be a good idea. The calcium being in solution at that concentration doesn't happen easily in a standard marine tank at an 8.3 alkalinity, with ordinary supplementation---when you drop lime (calcium) in, only 2 tsp per gallon CAN dissolve: the rest falls out as white powder. Which is where I run looking for Disk 1 or Bertoni over in Reef Chemistry asking 'is the alk also screwy?'
In general a calcium overdose is pretty benign, as when you od kalk powder and cloud your tank white: I've done it---many people who run kalk in topoff have had it happen. And it's a no-sweat. But with the situation you describe, I'd ask the CHemistry folk.

gone fishin · 05/08/2015, 01:56 PM

I agree with Sk8r. I also have very hard well water. we have a water softener for the house and my RO/DI is plumbed in after that.

skrivan · 05/08/2015, 02:33 PM

but the question really is this: in a 200 gallon tank that is definitely seeing high initial TDS, is it OK to do a 50 gallon water change every other day for a week?
thanks

gone fishin · 05/08/2015, 02:38 PM

If you sorted out the high TDS from your RO/DI, then I don't see why not.

disc1 · 05/08/2015, 07:18 PM

I wouldn't be too troubled by the high calcium reading. It will eventually come back down without doing any real harm. I would however be concerned with what might have come through along with the calcium.

05/08/2015, 11:57 AM	#1
skrivan Registered Member Join Date: Jan 2015 Posts: 6	question on RO-Di and water change: hi. sorry to add yet another water change thread, but I have no-where else to turn. 200 gallon DT with 75 gallon sump and here is my situation: I have a SPectra-Pure 90 Ro-DI which I use to make fresh water for water changes and also for an ATO reservoir. It's great, BUT, I just yesterday noticed that the DI chamber shows incredibly high TSD (over 135!) so I changed that filter. I had changed the filters (all) previously about 1 month ago, so I assumed I was good for awhile. I found a few corals, (a leather is mainly my concern) not opening up. I also checked all params and everything looks great except for very high calcium. I found that our water in Salt Lake City is super high in calcium (I tested tank calcium at 600 ppm). So, my ATO has been likely putting in water with high TSD and also the last 40 gallon water change I did was with high TSD water. Finally here is the question: should I do a very large water change, like 50% and do it every few days so I can minimize the TSD's I have in there? And, is it possible that the high calcium and TSD are a cause for come corals shutting down? Thanks.....joe

05/08/2015, 12:15 PM	#2
coralsnaked Registered Member Join Date: Jun 2012 Location: Austin / Port Aransas, TX Posts: 1,479	You need to check the TDS coming out of the RO membrane or the last DI canister on the RODI.system. Get an inline meter off the internet for $30 if you don't have one. No need to check for TDS in the DT as that's where all your livestock poo and excess food waste is. __________________ Merry Skerry Current Tank Info: 1 G Nano jellyfish to 1200 G Bull Nose FOWLR featuring large Holacanthus and Pomacanthus

05/08/2015, 12:44 PM	#3
Sk8r RC Mod Join Date: Feb 2006 Location: Spokane WA Posts: 34,628 Blog Entries: 55	This is where asking the chemists might be a good idea. The calcium being in solution at that concentration doesn't happen easily in a standard marine tank at an 8.3 alkalinity, with ordinary supplementation---when you drop lime (calcium) in, only 2 tsp per gallon CAN dissolve: the rest falls out as white powder. Which is where I run looking for Disk 1 or Bertoni over in Reef Chemistry asking 'is the alk also screwy?' In general a calcium overdose is pretty benign, as when you od kalk powder and cloud your tank white: I've done it---many people who run kalk in topoff have had it happen. And it's a no-sweat. But with the situation you describe, I'd ask the CHemistry folk. __________________ Sk8r Salinity 1.024-6; alkalinity 8.3-9.3 on KH scale; calcium 420; magnesium 1300, temp 78-80, nitrate .2. Ammonia 0. No filters: lps tank. Alk and cal won't rise if mg is low. Current Tank Info: 105g AquaVim wedge, yellow tang, sailfin blenny,royal gramma, ocellaris clown pair, yellow watchman, 100 microceriths, 25 tiny hermits, a 4" conch, 1" nassarius, recovering from 2 year hiatus with daily water change of 10%.

05/08/2015, 01:56 PM	#4
gone fishin Registered Member Join Date: Jul 2011 Location: Wyocena Wi Posts: 6,936	I agree with Sk8r. I also have very hard well water. we have a water softener for the house and my RO/DI is plumbed in after that. __________________ Tony Current Tank Info: 180gal DT, BM NAC77 skimmer,3 Maxspect razors, Maxspect Gyre 150, 30g QT

05/08/2015, 02:38 PM	#6
gone fishin Registered Member Join Date: Jul 2011 Location: Wyocena Wi Posts: 6,936	If you sorted out the high TDS from your RO/DI, then I don't see why not. __________________ Tony Current Tank Info: 180gal DT, BM NAC77 skimmer,3 Maxspect razors, Maxspect Gyre 150, 30g QT

05/08/2015, 02:33 PM	#5
skrivan Registered Member Join Date: Jan 2015 Posts: 6	but the question really is this: in a 200 gallon tank that is definitely seeing high initial TDS, is it OK to do a 50 gallon water change every other day for a week? thanks

05/08/2015, 07:18 PM	#7
disc1 -RT * ln(k) Join Date: Sep 2010 Location: Little Rock Posts: 9,705	I wouldn't be too troubled by the high calcium reading. It will eventually come back down without doing any real harm. I would however be concerned with what might have come through along with the calcium. __________________ David Current Tank: Undergoing reconstruction...