ICP results, Potassium low?

[CHSUB]

Today I got my third ICP results over the past year, K has dropped to 352. Not sure if any action is necessary, however I have 7 fast growing mangroves that require and consume K. Should I start testing and supplementing K? I did research K home test kits: Salifert $18.99 , Red Sea $63.99…huge difference? Any recommendations on K additives?

 

[Miami Reef]

Here’s my DIY potassium recipe:

https://www.reef2reef.com/threads/diy-potassium-dosing-for-reef-tanks.1110524/

Potassium chloride (food grade) is the best additive for potassium supplementation. Home test kits aren’t very accurate, so store a bottle of tank water and ensure the test kit result matches that ICP result of that sample prior to trusting future test results of the tank.

 

[UMALUM]

I use the aqua forest K and SR only because the calculator provided by @subodhs has them on the list. One thing ive noticed with the salfert K is that its always 20 to 30 higher than icp so just a heads up.

 

[Randy Holmes-Farley Verified Community Expert]

At 350 ppm, I’d dose potassium. It is cheap and easy. :)

 

[UMALUM]

At 350 ppm, I’d dose potassium. It is cheap and easy. :)

Randy, in your expertise when or at what levels do fish start to have a hard time? I can't seem to find an overall consensus but I do enjoy the benefits of running it higher than average.

 

[Randy Holmes-Farley Verified Community Expert]

Randy, in your expertise when or at what levels do fish start to have a hard time? I can't seem to find an overall consensus but I do enjoy the benefits of running it higher than average.

You mean too high? Lasse seems to have experience with fish problems at somewhat higher levels.

@Lasse

 

[UMALUM]

You mean too high? Lasse seems to have experience with fish problems at somewhat higher levels.

@Lasse

Yes

 

[CHSUB]

Thanks for sharing your thoughts…I ordered a K additive and the Salifert K test kit; will update when I test and receive. Not 100% sure, but maybe the leaves on mangroves could be a darker shade of green…hard to tell, but all corals look fine.

 

[UMALUM]

Thanks for sharing your thoughts…I ordered a K additive and the Salifert K test kit; will update when I test and receive. Not 100% sure, but maybe the leaves on mangroves could be a darker shade of green…hard to tell, but all corals look fine.

If your corals look fine at 350 wait till they get a couple weeks of 420.
Do you regularly mist your trees? When I used to grow them I would have to spray them when humidity was down or they would get pale.

 

[CHSUB]

If your corals look fine at 350 wait till they get a couple weeks of 420.
Do you regularly mist your trees? When I used to grow them I would have to spray them when humidity was down or they would get pale.

yes, I mist daily.

 

[CHSUB]

Received Potassium test kit today and tested twice, 340ppm after 6 gallon WC yesterday. ICP tested at 352ppm so it appears I need to dose K. I’m thinking ~ 400 should be my goal and going to assume 350 is my starting point. Will dose the correcting amount over the next 5 days while testing; 10 ppm per day. Thoughts?

 

[Randy Holmes-Farley Verified Community Expert]

Seems like a fine plan to me. :)

 

[CHSUB]

Been testing and dosing as planned and level is testing @ ~ 370 ppm after a couple of adjustments, however tested freshly mixed Reef Crystal and got 350ppm, same as ICP results on tank. So maybe source water(RC) is low and tank is actually not consuming K beyond what is in foods? Still going to proceed with plan but wondering if 350 ppm K is an acceptable level since never noticed any negatives in tank?

 

[Randy Holmes-Farley Verified Community Expert]

Been testing and dosing as planned and level is testing @ ~ 370 ppm after a couple of adjustments, however tested freshly mixed Reef Crystal and got 350ppm, same as ICP results on tank. So maybe source water(RC) is low and tank is actually not consuming K beyond what is in foods? Still going to proceed with plan but wondering if 350 ppm K is an acceptable level since never noticed any negatives in tank?

I dont really know how low if potassium is ok.

Are you confident in the salinity of your new salt water?

 

[CHSUB]

I dont really know how low if potassium is ok.

Are you confident in the salinity of your new salt water?

Yes, reasonably confident. Pictured is new sw on Milwaukee just tested and ICP from tank. The Milwaukee, which I always calibrate, shows 35 PSU on tank and lists are error of +/- 1, so it seems good compared to ICP. I double check with refractometer also.

 

[UMALUM]

Been testing and dosing as planned and level is testing @ ~ 370 ppm after a couple of adjustments, however tested freshly mixed Reef Crystal and got 350ppm, same as ICP results on tank. So maybe source water(RC) is low and tank is actually not consuming K beyond what is in foods? Still going to proceed with plan but wondering if 350 ppm K is an acceptable level since never noticed any negatives in tank?

It's gotta be the reef crystals. These are my numbers from my last icp collected the day after a 40% wc. Both salfert kits read 360 against this 337 so I'm confident salfert reads high.

 

[CHSUB]

It's gotta be the reef crystals. These are my numbers from my last icp collected the day after a 40% wc. Both salfert kits read 360 against this 337 so I'm confident salfert reads high.

Very interesting….are you going to add K?

Thanks, I was questioning what was going on, but now feel reasonably confident that Reef Crystals is low in potassium.

 

[UMALUM]

Very interesting….are you going to add K?

Thanks, I was questioning what was going on, but now feel reasonably confident that Reef Crystals is low in potassium.

Yeah, I brought it up to 420 over a 6 day period ? Might go to 450 but don't want to give the fish headaches.

 

[rtparty]

Trusting any home test kit for K is a ticking time bomb. They are notoriously inaccurate and unreliable

 

[Randy Holmes-Farley Verified Community Expert]

Yes, reasonably confident. Pictured is new sw on Milwaukee just tested and ICP from tank. The Milwaukee, which I always calibrate, shows 35 PSU on tank and lists are error of +/- 1, so it seems good compared to ICP. I double check with refractometer also.

The icp says 33.9. If you raised it to 35 ppt, 350 ppm potassium becomes 361 ppm. Still worth dosing up, IMO.