Carbon dosing

emoore · Jan 8, 2023

Weekly update. Nitrate holding steady at 17.9. Phosphate is 0.18. Replaced GFO so should go down a bit. Still dosing 1ml ElimiNP I’m happy with these levels. might switch to balance soon. Corals are doing well.

Coolcasino · Jan 9, 2023

Are you manually dosing? I think that's one of the reasons I haven't switched from NoPox. Elimi NP is so concentrated that it doesn't need much. That and I'm already dosing A and K from TM and elimi np has K in it I believe. My PO3 are around 15 still and PO4 is dropping steadily with rowaphos. Seem to be at 40 now. I did change it yesterday so I I will know tomorrow when I test. Did a water change today so PO3 should be down a bit and we will see where the PO4 is sitting after the rowaphos refresh..

emoore · Jan 9, 2023

Coolcasino said:
Are you manually dosing? I think that's one of the reasons I haven't switched from NoPox. Elimi NP is so concentrated that it doesn't need much. That and I'm already dosing A and K from TM and elimi np has K in it I believe. My PO3 are around 15 still and PO4 is dropping steadily with rowaphos. Seem to be at 40 now. I did change it yesterday so I I will know tomorrow when I test. Did a water change today so PO3 should be down a bit and we will see where the PO4 is sitting after the rowaphos refresh..

yep manually dosing ElimiNP at 1ml a day. I hope you mean 0.15ppm NO3 and not phosphate. ElimiNP works well bringing down NO3 but not so much PO4.

14 foot reef · Jan 9, 2023

emoore said:
Weekly update. Nitrate holding steady at 17.9. Phosphate is 0.18. Replaced GFO so should go down a bit. Still dosing 1ml ElimiNP I’m happy with these levels. might switch to balance soon. Corals are doing well.

You did great on this not overeacting and following the adive that youask for on this awesome forum....Bravo !!!

Randy Holmes-Farley · Jan 9, 2023

emoore said:
Nice. I’ve noticed the same thing. Carbon dosing can bring down nitrates but not much help with phosphates.

That is normal and expected for two reasons:

1. Denitrification is driven by organics, and it consumes nitrate and not phosphate.

2. Much of the total phosphate in a reef aquarium can be temporarily bound to rock and sand, strongly buffering the rise and fall of phosphate concentration. Thus adding or removing 0.1 ppm of phosphate from the water (in any way) may result in a far lower actual change in phosphate.

Coolcasino · Jan 9, 2023

emoore said:
yep manually dosing ElimiNP at 1ml a day. I hope you mean 0.15ppm NO3 and not phosphate. ElimiNP works well bringing down NO3 but not so much PO4.

Yup. My bad. Nitrates are 0.15 and Phosphates 0.40. Wish NoPox did the opposite. Nitrates can somewhat come down with water changes but phosphates are a pain to bring down. If I can get the Phosphates down also maybe I will try the TM balance. I just want to try to use 1 thing and eliminate the Rowa... but if I need to always use some sort of GFO so be it.

Koty · Jan 10, 2023

Randy Holmes-Farley said:
. Much of the total phosphate in a reef aquarium can be temporarily bound to rock and sand, strongly buffering the rise and fall of phosphate concentration. Thus adding or removing 0.1 ppm of phosphate from the water (in any way) may result in a far lower actual change in phosphate.

I did not consider that the dissolved phosphate is in a dynamic steady state with bound phosphate. The good side of it is that it helps avoiding exrteme changes. I just reinstalled⁴ my GFO reactor after finding that carbon dosing does not cope with the phosphate load in my tank. I have it on very low flow. Now i will increase the flow to get to below 0.1 ppm

Randy Holmes-Farley · Jan 10, 2023

Koty said:
I did not consider that the dissolved phosphate is in a dynamic steady state with bound phosphate. The good side of it is that it helps avoiding exrteme changes. I just reinstalled⁴ my GFO reactor after finding that carbon dosing does not cope with the phosphate load in my tank. I have it on very low flow. Now i will increase the flow to get to below 0.1 ppm

Yes, it does slow down changes up or down.

emoore · Jan 12, 2023

14 foot reef said:
You did great on this not overeacting and following the adive that youask for on this awesome forum....Bravo !!!

Thanks for the support. Tank is doing so much better. Thankful for all the help here including the famous Randy Holmes-Farley. Been following his advice since that other large reef forum that used to be “central” to the reefing community.

Coolcasino · Jan 18, 2023

Tested today. NO3 7.5 & PO4 0.19. Small drop in NO3 since my last test which was 15.0 and backed off 1 dose of NoPox. No water change this week either so seems to be working. Rowaphos dropped PO4 nicely from 2 weeks ago at 0.40. Seems I've been able to drop both in half. Hopefully I keep NO3 where it is and drop PO4 to under 0.10.

emoore · Feb 6, 2023

Another update. I might have figured out one of my issues. I had something go wrong with my RO membrane and was getting very high TDS water for top off and new saltwater. Guess I should have tested it more often. Replaced the membrane and filters, back down to 0 tds. Also added an inline tds monitor.

Due to the bad water I made all new top off and saltwater. Replaced 20% yesterday. Nitrates are 18 and phosphate 0.08. Much better. Now I just need to keep everything stable without anything going wrong.

Coolcasino · Feb 6, 2023

NoPox is handling my no3 nicely. Under 10.0 with small water changes. Po4 is another thing. Rowaphos can't keep it down. 0.30 with 8 tbsp in a 125g. It gets exhausted in a few days.