Added a refugium...Low Nitrates now

[ReeferFive-0]

I recently added a refugium to the back chamber of my Biocube 32 and my nitrates are dropping really low. Here's my setup:
32 gallon biocube with the In Tank tower/media basket with Marine Pure biological filtration in the top chamber and chaeto in the bottom chamber (with a few more bio media balls in the bottom to keep chaeto off the bottom and keep good flow through basket). I have a the 12 Watt In Tank refugium light on the chaeto set to the opposite schedule of the aquarium light (on from 9pm to 11 am). I have an Eshopps nano skimmer in the second chamber right after the media basket. I have been doing 10-15% water changes weekly and add some Microbacter 7 and ChaetoGro following weekly maintenance. Here are my current parameters:
SG: 1.025
Nitrate: 0.5
Phosphate: 0.08
Alk: 9.3 dKH
Ca: 470
Mag: 1350

On 3/7, just before adding the refugium my Nitrate sat at 3.1 and Phosphate at 0.06 after doing a large water change. So nitrates are going way down and phosphate is slightly up.

I really don't want to dose anything else if I can help it. Here are some steps I'm contemplating to resolve this.
Cut down on how long the refugium light is on, feed more, stop protein skimming, stop dosing Microbacter 7. Any suggestions on which of these would be most beneficial would be appreciated.

Thank you

 

[VintageReefer]

I really doubt that refugium is responsible. But, it could be.

First thought - do nothing. Don’t panic. You made a change to your system and things need to balance. Give it at least a month and if you are testing at the same time and getting consistent low numbers then decide if action needs to be taken

1) how are your corals? If corals look good and are normal you might not need to do as nothing

2) harvest the cheato. - remove 25-50%
This will be a normal thing anyway as that compartment gets full.

3) reduce fuge lighting from 14 hours to 12 and retest in a week

 

[ReeferFive-0]

I really doubt that refugium is responsible. But, it could be.

First thought - do nothing. Don’t panic. You made a change to your system and things need to balance. Give it at least a month and if you are testing at the same time and getting consistent low numbers then decide if action needs to be taken

1) how are your corals? If corals look good and are normal you might not need to do as nothing

2) harvest the cheato. - remove 25-50%
This will be a normal thing anyway as that compartment gets full.

3) reduce fuge lighting from 14 hours to 12 and retest in a week

Thanks for the reply. Since adding the chaeto less than 3 weeks ago, it tripled in size and I removed half of it last night along with a water change. My nutrients would go up and up within a few weeks prior to making this change so I'm convinced it's the chaeto that's making an impact. I just want to make sure I'm balancing Nitrate and Phosphate levels well over time. I'll continue to monitor and adjust accordingly if the trend continues.

 

[ReeferFive-0]

I just wanted to update this thread, as I think I'm on the right path to keep nitrate and phosphate more stable. On 3/26 nitrate was at 0.5 and phosphate at 0.08. I did a 5 gallon water change (on Biocube 32) and the next day nitrate was at 0.2 and phosphate at 0.13 (I fed heavy handed that week). So my nitrates continued to drop while phosphate rose. I came to the conclusion that my system is nitrate limited and dosed Nyos Nitrate+, bringing the nitrate up to 3.2. Now it's 5 days later and I tested again without a water change and my nitrate is 2.6 and phosphate at 0.10. The chaeto has been growing like crazy after the nitrate dosing bringing both nitrate and phosphate down in the process. I'll be dosing nitrate to keep these parameters in check and am optimistic this will keep things stable long term.