Beginning dosing questions

thabizness · 02/22/2014, 11:56 AM

I am now at the point which my Alk is not being kept up with water changes and would like to start dosing. I would like to keep my alk about 153-155ppm. Using a hanna meter my numbers change from 153ppm to 133ppm over 5 days giving me a change of 4ppm per day. I would like to do water changes every other week. I use ReefCrystals for salt. My concern is that if I add 4ppm per day to keep up with consumption how do I account for the increase from the water changes?

How do you guys dose but still account for Alk while using reef crystals which tend to be high in Alk?

Reef Frog · 02/22/2014, 09:35 PM

Usually a 10% water change doesn't account for much of an ALK swing, at least with the salt I use. If your salt is rich enough to make a change you don't want, you could always experiment with not dosing the day before and day after the water change for example and adjusting that based on your test results. Or you could split your WC into 2 water changes.

bertoni · 02/23/2014, 04:46 PM

I was too lazy to try to target different parameters than the saltwater, although IO was lower in alkalinity then. If you change the same amount of water each week, we could calculate how the dosing should be done given a few measurements. One before and after the water change would help.

reefdude3749 · 02/23/2014, 08:06 PM

I agree with Jonathan....if given a few parameters this can be quickly calculated. Another couple of options would be to prove (through similar calculations) if the 10% water change is going to have a material impact on your parameters....or you could use a salt that mixes closer to your desired tank parameters...Again, a few typical numbers from your system and this can be calculated....but understand that as you add things this equations will be ever changing.

thabizness · 02/24/2014, 03:19 PM

I tend to do 10 gallons twice a month. I did a water change yesterday and the change in alk was 9ppm/.504 dKh after a few hours. So I could just not dose for two days after the change. This would swing alk .504 dKh with the doser kicking on after end of 2nd day.

It almost seems like the best way is to set my alk to what the water change is and dose from there. If the goal is stability a .5 dKh breaks that.

bertoni · 02/24/2014, 04:19 PM

I think most corals should be fine with a 0.5 dKH swing. I'd give it a shot.

Crusinjimbo · 02/25/2014, 06:42 AM

Extract a known volume of tank water and test ALK. Change 10% with thoroughly mixed FSW and measure ALK again. This should ballpark the effect of a full 10% chage in your tank. I use IO salt and my test resulted in a negligible change that I could only measure with my Hanna.

02/22/2014, 11:56 AM	#1
thabizness Registered Member Join Date: Sep 2012 Location: Sooo St. Louis Posts: 363	Beginning dosing questions I am now at the point which my Alk is not being kept up with water changes and would like to start dosing. I would like to keep my alk about 153-155ppm. Using a hanna meter my numbers change from 153ppm to 133ppm over 5 days giving me a change of 4ppm per day. I would like to do water changes every other week. I use ReefCrystals for salt. My concern is that if I add 4ppm per day to keep up with consumption how do I account for the increase from the water changes? How do you guys dose but still account for Alk while using reef crystals which tend to be high in Alk?

02/23/2014, 04:46 PM	#3
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	I was too lazy to try to target different parameters than the saltwater, although IO was lower in alkalinity then. If you change the same amount of water each week, we could calculate how the dosing should be done given a few measurements. One before and after the water change would help. __________________ Jonathan Bertoni

02/24/2014, 04:19 PM	#6
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	I think most corals should be fine with a 0.5 dKH swing. I'd give it a shot. __________________ Jonathan Bertoni

02/25/2014, 06:42 AM	#7
Crusinjimbo Registered Member Join Date: Dec 2008 Location: Wesley Chapel FL Posts: 751	Extract a known volume of tank water and test ALK. Change 10% with thoroughly mixed FSW and measure ALK again. This should ballpark the effect of a full 10% chage in your tank. I use IO salt and my test resulted in a negligible change that I could only measure with my Hanna. __________________ Jimbo 13.5G EVO

02/22/2014, 09:35 PM	#2
Reef Frog Registered Member Join Date: Feb 2013 Location: Maryland Posts: 3,121	Usually a 10% water change doesn't account for much of an ALK swing, at least with the salt I use. If your salt is rich enough to make a change you don't want, you could always experiment with not dosing the day before and day after the water change for example and adjusting that based on your test results. Or you could split your WC into 2 water changes.

02/23/2014, 08:06 PM	#4
reefdude3749 Registered Member Join Date: Sep 2012 Location: Michigan Posts: 77	I agree with Jonathan....if given a few parameters this can be quickly calculated. Another couple of options would be to prove (through similar calculations) if the 10% water change is going to have a material impact on your parameters....or you could use a salt that mixes closer to your desired tank parameters...Again, a few typical numbers from your system and this can be calculated....but understand that as you add things this equations will be ever changing.

02/24/2014, 03:19 PM	#5
thabizness Registered Member Join Date: Sep 2012 Location: Sooo St. Louis Posts: 363	I tend to do 10 gallons twice a month. I did a water change yesterday and the change in alk was 9ppm/.504 dKh after a few hours. So I could just not dose for two days after the change. This would swing alk .504 dKh with the doser kicking on after end of 2nd day. It almost seems like the best way is to set my alk to what the water change is and dose from there. If the goal is stability a .5 dKh breaks that.