Can't figure out my parameters

[Leyth]

Hey guys, for the past few weeks I have been trying to get my mag, alk, and calc to optimal levels and I'm not really noticing any change. The aquarium is a 17 gallon and I water change 4 gallons every Sunday. I usually test parameters right before I do the change. I noticed that the numbers never changed. So, I assumed that the corals are just taking all those elements out of the water by the time next water change came around. I was going to up my water changes to twice a week. However, I decided to test my parameters today, which is monday, the day after I tested and did a 4 gallon water change. I was surprised to find that the parameters all stayed the same. Does anyone have any idea what is causing this or what I need to do differently?

Here are my numbers:
-PH: 8.2
-Temp: 78 F
-Sal: 1.026
-Alk: 6 dkh
-Mag: 1320 ppm
-Cal: 400 ppm
-Nitrates: 0-5ppm

Here are details about the equipment that I could see effecting parameters:
-BRS 6 Stage RO/DI unit that is 3 months old
-Tunze auto top off
-Radion XR30W Gen 3 on SPS+ Coral Labs setting for 10 hours a day
-Aquamaxx hob-1 skimmer (added this 2-3 weeks ago, really didn't change anything though)

Maintenance and feeding schedule:
-4 gallon water change weekly
-scrape glass on the 3 viewing sides every 2-3 days
-auto feeder drops hikari marine s pellets once a day in the afternoon(very small amount, the fish take care of every single piece in about 30 seconds)
-feed LRS, Rods, or PE mysis every 1-3 days
-spot feed reef roids once a week to the corals

Live stock:
-2 small snowflake clownfish
-1 tiger pistol shrimp
-1 RBTA
and a bunch of corals that you can see in the pic below:

 

[skim]

If you are wondering why your numbers do not drop, well you do not have much in the tank to remove it in 7 days time. You may want to try every 2 weeks. Do you have any kind of surface skimming? I see quite a thick film on the surface and that would block your light quite a bit and keep Co2 looked in.

 

[Jason mack]

Your alk seems a little low .. what test kits are you using and salt mix ?

 

[Randy Holmes-Farley]

The alk is low, and when alk is low, demand (if the tank otherwise would have any) drops.

Boost the alk with an alk supplement, not a water change, which is a poor way to maintain alkalinity.

 

[Leyth]

I am using Red Sea Coral Pro salt

 

[Leyth]

If you are wondering why your numbers do not drop, well you do not have much in the tank to remove it in 7 days time. You may want to try every 2 weeks. Do you have any kind of surface skimming? I see quite a thick film on the surface and that would block your light quite a bit and keep Co2 looked in.

Yes, this film is driving me nuts and I cannot figure out what is causing it to occur and what to do to get rid of it. My MP10 agitates the surface a little and the skimmer agitates it even more. I use paper towels to soak it up every few days, but it always comes back.

Your alk seems a little low .. what test kits are you using and salt mix ?

API test kit for everything except magnesium is salifert

The alk is low, and when alk is low, demand (if the tank otherwise would have any) drops.

Boost the alk with an alk supplement, not a water change, which is a poor way to maintain alkalinity.

Is baking soda a good route to take?

 

[Randy Holmes-Farley]

Yes, this film is driving me nuts and I cannot figure out what is causing it to occur and what to do to get rid of it. My MP10 agitates the surface a little and the skimmer agitates it even more. I use paper towels to soak it up every few days, but it always comes back.



API test kit for everything except magnesium is salifert



Is baking soda a good route to take?

If pH is low, use baked baking soda (sodium carbonate) for both an alk and pH boost. :)

 

[Jason mack]

I am using Red Sea Coral Pro salt

I was under the impression Red Sea pro was high in alk when mixed .. I wouldn't trust your API test maybe get a Red Sea or saliferts test !

 

[Randy Holmes-Farley]

I was under the impression Red Sea pro was high in alk when mixed .. I wouldn't trust your API test maybe get a Red Sea or saliferts test !

Did he test the new salt water and find it low? If he did, I missed that.

That said, water changes are not normally adequate for maintaining alkalinity, regardless of the mix used. :)

 

[Leyth]

Did he test the new salt water and find it low? If he did, I missed that.

That said, water changes are not normally adequate for maintaining alkalinity, regardless of the mix used. :)

Nope, I tested the aquarium after doing the water change. I've never tested the newly mixed water itself and as I am typing this I am realizing why I should have haha. I will test newly mixed water today to confirm whether its a testing error or not.

 

[Leyth]

Ok I tested freshly mixed water and I got 11-12dkh so I guess my test isn't far off since Red Sea Coral Pro Salt suggests 12dkh. So I guess I am going to move forward with boosting alk?