[acidrain]

Update:
I titrated my tank today, and had some interesting results...
The following method and parameters are for profesional tanks, so I expected the acid concetration of my tank to be less than normal. It was not.
I have never added aluminum sulfate to my tank, so I expected it to be low. It was.
My acid ratio was 122 gr./L... 180 to 200 is prefered.
My alum. ratio was 1.8 gr./L... 10 to 15 is prefered.
Maybe the low aluminum caused a relative high acid reading. I'll try taking a gallon or so of my acid solution, and add the aluminum sulfate, re-titrating this small batch as an experiment.

Here is the method:

Here is what you will need to titrate your anodize tank and keep it within operating parameters.

1. 0-50ml burette (recommend self zeroing burette)
2. 400ml beaker
3. magnetic stir station
4. stir bar
5. bottle of lab grade 1.0 N NaOH reagent (sodium hydroxide)
6. hand help ph meter
7. 0-10ml Pipette (I have one that I can give you.)
8. PH Buffer Solutions to calibrate PH probe. Get a 3.01, 7.01 and 10.01

TITRATION INSTRUCTIONS

1. FILL BURETTE WITH NaOH
2. PIPETTE 5 ML OF ANODIZE BATH INTO 400ML BEAKER
3. ADD 200ML OF DI WATER TO BEAKER
4. PLACE STIR BAR IN BEAKER AND SET ON MAGNETIC STIR STATION
5. PLACE TIP OF PH PROBE INTO BEAKER CAREFULLY AVOIDING CONTACT WITH STIR BAR
6. SLOWLY ADD NaOH TO BEAKER FROM BURETTE. ADD UNTIL PH METER READS 3.6 THEN RECORD READING FROM BURETTE. THIS IS READING A
7. CONTINUE TO ADD NaOH UNTIL A PH OF 8.5 IS REACHED. RECORD NEXT READING FROM BURETTE. DO NOT TOP OFF BURETTE BETWEEN READINGS. THIS IS READING B

CALCULATION

G/L H2SO4 (SULFURIC ACID) = A x 9.8
G/L ALUMINUM: = (B-A) x 1.8

You want your target of g/l of H2SO4 to be between 180-200 g/l
You want your target aluminum to be between 10-15 %

If you’re over 15% remove half of your bath and top off with DI water then re-titrate. If your aluminum content is below 10% calculate how many pounds of aluminum sulfate to add to the bath to bring it back up to 10%.