reasons for low ph and alk ???

This is my first posting on 3reef. I have a 90 gal mixed reef with led lighting. The current problem that I am having is that I am unable to bring up my ph or alk and my cal levels are high my levels are as follows.
ph= 7.8
Nitrate=0
Nitrite=0
Calc=480
Phosphate=0.01
Alk=5.6 Dkh
I do not have a cal reactor but have been dosing for the last year with seachems reef complete 3 caps every other day
seachem reef carbonate 4 caps every other day (opposite complete)
seachem reef iodide 2 caps 2 times a week
My lfs seems to think that getting water from my ro unit after my water softner may be adding chemicals that are reacting with my dosing causing the low levels.

 

What's your magnesium at? If your magnesium is low if you try dosing alkalinity it will likely mostly precipitate out without raising your levels. I don't think 480 is too high for calcium btw. I try and maintain 450 calcium, 8-9 alkalinity and 1400+ magnesium.

Here's a good article about overall chemistry if you want more info.
The “How To” Guide to Reef Aquarium Chemistry for Beginners Part 2: What Chemicals Must be Supplemented by Randy Holmes-Farley - Reefkeeping.com

 

Thanks for the reply. I was thinking that this may be a possibility but currently do not have a test kit for magnesium but will look into getting one tomorrow when my lfs is open.

 

do you have a cover on your tank...high amount of CO2..closed house, tight windows, lids etc will cause your pH to drop.
Also you have been dosing the same amt for a year...has your corals grown, lot of coralline, increase in corals? If so you will have to increase your dosing. I know when my coral growth took off, I couldnt keep up with the demands and had to completely refigure everything out.

Also..are you testing for iodine? You really dont need to dose iodine and if you do you need to test for it..can kill lots of things very fast

 

My iodine level is at 0.06 I have a lot of soft corals in my tank that seem to use it up fairley quickley. I do not have a glass top on the tank but I do have a canopy with the only vents at the back of the canopy and 4 holes on top that just vent the heatsinks for the led fixtures.
Lack of room ventilation may possibly be a cause we are away from home until 6 then we usually open a door or window to circulate some air through the house.
I have changed my dosing based on coral growth but I am currently dosing bases on the seachem instructions almost 2 times what I should be and my current levels are still low.

 

Well I was just at my lfs purchasing my magnesium test kit. While there I also decided to purchase a new rodi unit sinse the unit that I was using was ro only.
I tested my magnesium and foud it to be at 1350 ppm so it seems as though this is not my problem.
I am going to start doing a few small water changes with my new rodi unit within the next couple weeks and hopefully this will correct my problems. Thanks for all the replys.

 

i had a similar problem when i added a cement rock to my tank that had'nt cured long enough

 

I have not added any live rock to my tank in about 7 or 8 months

 

Stop dosing the Calcium, and keep up your regular alk dosing. Also, make sure your kit is reading right. Maybe have your LFS or a friend test your parameters and see what they get. A couple 10-20 percent water changes wouldn't hurt either.