Low alkalinity/won't rise

[WannaRace]

Hey gang,

I've been using an algae scrubber for quite some time now with fantastic results. Corals look great, fish are fat and happy, and my cyano is gone.

We've discovered that algae scrubbers suck up alkalinity! So, I am here with this problem.

My alkalinity tests at 4.8dkh. I've dosed 1 tsp. of baking soda each evening for 2 weeks with no change in alkalinity. This week, I've upped it to 2 tsp. each evening. This is day 2 and I decided to test since I increased dosage. Alk = 4.8 still! This is a brand new salifert test kit backed up by my API kit. Why won't it budge?

I'm also dosing 10ml B Ionic calcium each morning
No water change since February 2012...
Other params:
Ph 8.0 (4pm test, lights out at 7pm)
Ca 420
Salinity 1.024
Nitrate 0
Nitrite 0

I've also got SeaChem Marine buffer. Anyone have any experience? I might try this next week if I get no results with baking powder.

 

[Smitty]

Why haven't you done a water change in so long? I don't think an algae scrubber should influence your alkalinity negatively. Maybe you should check your magnesium, because if your magnesium is off, then your alkalinity and calcium will be off also.

 

[d2mini]

+1 Smitty. Check that mag.

 

[ccCapt]

Hopefully you aren't dumping the dry baking soda directly into the tank. You MUST mix it with some fresh water. In 75g of water, 1 tsp of baking soda will only raise the alk 0.6 dKH and 2 tsp aprox 1.15 dKH. Being you haven't done a water change in so long (dunno what the reasoning behind that would be) you definitely need to check your mag. A very low mag level would cause the alk to precipitate out of the water column pretty fast and prevent the alk level from rising.

I might try this next week if I get no results with baking powder.

I hope you really meant baking soda.

 

[WannaRace]

My mistake. I was previously adding .5 teaspoons per evening for 2 weeks. I am now going to add 1 teaspoon per evening for 1 week.

I added 8 teaspoons of baking soda :) to 1 gallon of RO water. I add 2 cups (1/2 cup every 45 minutes) per night.

Water changes are not necessary with an algae scrubber. My water quality is still excellent besides this blip. If it comes down to it I may just do a 15% change. I'm not opposed to that.

 

[bjohanson1234]

My mistake. I was previously adding .5 teaspoons per evening for 2 weeks. I am now going to add 1 teaspoon per evening for 1 week.

I added 8 teaspoons of baking soda :) to 1 gallon of RO water. I add 2 cups (1/2 cup every 45 minutes) per night.

Water changes are not necessary with an algae scrubber. My water quality is still excellent besides this blip. If it comes down to it I may just do a 15% change. I'm not opposed to that.

Water changes aren't necessary to reduce nitrates. They are still necessary to replenish trace elements that are getting used up by your corals.

 

[little_fish]

+1 BJ

There is nothing you can add to your tank that will replace the need for regular water changes

 

[yote]

+2 Bj.
You wouldn't wait until your vehicle has thrown a rod through the engine before changing the oil would you? Why wait until you have a problem with the tank before doing a water change?

 

[Cathic]

+3 BJ and yote and everyone... No need to expect a miracle out of a scrubber...

 

[WannaRace]

Well, I did about a 15% water change and a few hours later I checked the alkalinity. It still sits at 5.4 dKH. I thought a PWC would at least put a dent in that number, but nothing. Maybe next week I will mix up another batch with some pH/alk buffer and change again...

 

[bjohanson1234]

Well, I did about a 15% water change and a few hours later I checked the alkalinity. It still sits at 5.4 dKH. I thought a PWC would at least put a dent in that number, but nothing. Maybe next week I will mix up another batch with some pH/alk buffer and change again...

Going from 4.8 to 5.4 is a decent improvement. Keep up with those water changes and it will get back to a good range.

 

[bjohanson1234]

For example, say you new water mixes to 7dkh and your original water is at 4.8dkh. You are doing a 15% water change. 85% of the water will be old water at 4.8 and 15% will be new water at 7. So your final value should be around

.85x4.8 + .15x7 =
4.08 + 1.05 =
5.13

One PWC isn't going to reverse a long term problem. A regular schedule of PWC will.

 

[d2mini]

Did you ever check your magnesium?

 

[ccCapt]

BJ did the math for you. What you got is what should be expected.