Stupid or Crazy? Lye in my kalk chamber.

[RSnodgrass]

My kalk chamber ran out and needed to be refilled. Typically I fill it up 4-5" at a time so it lasts a bit over a month. I'd like to boost my pH & alk more than what it provides because evaporation limits how much I can dose. Using a kalk slurry it's appealing for a few reasons. Namely, I'm using All For Reef which is why alkalinity tends to run on the low side. My tank is in my office so there's alot of CO2 pressure on the system each day. I also don't need the extra CA provided by kalk.

Is what I'm doing working? Yes. Can it be better? Dunno. Is lye the solution? Dunno...

I've previously used this to melt zoa (quite successfully) so I'm somewhat familiar with the likely challenges. Most of which I predict will result in a failure.
Another solution is of course just filling a jug with a pre-determined amount of lye and water. A seriously burning and effective idea with the right equipment.

Pros:
- Very potent method of raising pH and alkalinity. Both of which I need.
- Can come in a "sand like" form. Thus *less dangerous and likely to be aerosoled.

Cons:
- Highly caustic... remember Fight Club?
- Slippery and doesn't just "rinse off". It can also creep along a surface at times, ending up where you didn't plan.
- It crystalizes once it hits water and again once past the saturation point. This can turn your tubing and chamber into a brick if not agitated enough.
- Highly exothermic so you likely can only add a little at a time or you risk the chamber getting too hot and being damaged.

*Danger Will Robinson! It'll burn your skin, eyes, organs, etc. Wear appropriate ppe & plan for an accident/spill so you are prepared to clean up safely when needed.

*This is on a 300gal 4yr old mixed reef.

4yr Tank-aversay!

In 20yrs this has officially been my favorite system. Hopefully in several more it will officially be my longest successfully running reef display. www.Slide-Loc.com

rumble.com

 

[RSnodgrass]

Initial observations:

Before adding, yes this is a Instagram worthy designer sump space.

Modified stir bar up close (love this for kalk & this Avast reactor is a beast!).

I put in a 1/4th cup at a time, careful to have drained down the reactor part way prior so slurry would not overflow into the tank.

At a 1/4th cup it got hot near the base like a cup of coffee. I continued to add about every 10min.

The stir bar potentially would have stalled out had I added more at a time. This again is because it crystallizes when it hits water. It was definitely chugging along at times.

It fully dissolved the 2 lbs, I was not expecting this. 4 lbs ordered on Amazon.

After adding 2 lbs. and dissolved.

 

[RSnodgrass]

Apex starting results:

*Keep in mind... my kalk ran out, I'm running a low initial dose of this sodium hydroxide, and I'm likely going to have to adjust my All For Reef dose as a result of all of this.

2 weeks ago, prior to kalk running out:

Programming prior for kalk:

Current readings:

Last week to present:

1 day view:

1hr view, you can see the first dose:

New Programming:
3 sec every 30min which is effectively like 1 second actual due to normal Apex switch lag.

I increased my trident testing to 8x a day.

 

[RSnodgrass]

I'm sure someone has tried this... I did not find it, so here we are.

 

[RSnodgrass]

My alk is crashing from kalk no longer dosing so I bumped up my dose from 3 sec every 30 min to 5 sec every 15 min.

 

[RSnodgrass]

Reduce to 3 sec every 20 min.

I had reduced last night to 3 sec every 15 min because my pH limiting factor kept it from running most of the time.

You can't really reduce to less than 3 sec with the apex due to the hardware limitations so now extending time between doses.

Running an actual dosing pump (that does not loose programming when powered off) is probably the way to go.

The dosing would still push water in and gravity out. I'm hesitant for now about buildup in a hose line like kalk does. I just don't know if it would. It mostly likely needs to be dropping into the sump vs. an output directly touching the water. That's a problem with kalk... maybe not with lye.

Having two pH probes I'd say is also critical. In the same way a double heater is. It's the highest point of failure.

 

[RSnodgrass]

Well this is perhaps short lived, at least for this initial container. My initial research showed acrylic to be compatible through several sources.

When researching alternatives for simple do a dosing pump and container I came across several others saying 'not so fast'. Basically it's fine but most likely not at the concentration I'm looking at.

A friend previously mentioned this which I'll take into consideration for use with dosing...
"Speaking from experience, MurLok polyethylene tubing holds up great to heavy alkalines for years with no change. Vinyl/pvc tubing turns black and gets brittle. I use it at work for carwash chemicals. You’ll also want to watch any seals it contacts. Anything besides EPDM will melt. I suspect only one you have in this setup would be the union on the reactor which isn’t really vital."

Various Tygon Tubing like pharmed are well rated for use in the dosing pump if 50% concentration or less.

Here are the know plastics for containment that invariably work best. A stir bar application could still work but a different container is needed.

 

[HuduVudu]

Make sure you are water changing because you are adding sodium also without any way to balance it.

 

[RSnodgrass]

Make sure you are water changing because you are adding sodium also without any way to balance it.

Good additional point, yes I've got a daily change out. Currently the actual ml addition is extremely small so this should be easily compensated for.

 

[RSnodgrass]

Well I've been futzing trying to set up a similar system to my kalk stir but at this point I don't see the point for several reasons.

I ordered a Polypropylene jug capable of handling 85% concentration. IE 85g of sodium hydroxide for every 15ml of water.
Here
Thus mixing in 2 lbs (907g) of it will be at a concentration of 22.6%.

I have pharma grade tygon tubing capable of 40% concentrations. Already on hand which will be a constant run from the jug through the dosing pump to the tank.

I ordered John Guest bulkhead because it uses Polypropylene plastic and EPDM gaskets.
Here

I'll figure out how to run through the bulkhead next. I could just dangle the tube in the jug without a bulkhead however I'd like to prevent the tube from ever sliding and then getting outside the container.

The pH boost continues to be massive while making tweaks. A less concentrated version will help with dosing control as well given the pump I'm using.

 

[RSnodgrass]

Temperatures below 70 degrees will potentially cause the solution to solidify so under the stand will be a great place for it.

It will be stored below the water line so that the height of the tube will remain above the height of the container and prevent back siphon.

Doing this will also allow the tube height to remain close to the water and prevent unnecessary splashing. Those concentrated splashes could damage my acrylic sump over time.

 

[RSnodgrass]

I may start diluting even more as the current concentration has a dramatic impact on pH even on 300 gal with 800 gph turnover in my sump. Either that or I need to hook up a slower dosing pump.

Regardless my pH is on point.
My alk is now averaging a full point higher as well.

Forgot the polyethylene tubing used in RO is also highly compatible so I'll change over to that on some parts.

 

[reef_ranch]

What volume are you dosing?

 

[RSnodgrass]

What volume are you dosing?

I honestly have no idea, it's a spectra pure dosing pump which moves pretty fast. All I can say it physically runs for 2 sec every 15 min for about half the day (overnight) as the pH stays above 8.3 during the day in spite of 4-8 people in the office all day.

 

[nereefpat]

Sodium Hydroxide could work okay for alk and a bonus pH boost.

I believe the pH boost will be the same as using limewater. As in 0.5 dKH from lye will boost pH the same as 0.5 dKH from limewater.

I also believe the dry stuff is about twice as concentrated as sodium carbonate.

I would not use a stirrer for this. I would mix up a solution by hand and dose with a dosing pump.

 

[reef_ranch]

Sodium Hydroxide could work okay for alk and a bonus pH boost.

I believe the pH boost will be the same as using limewater. As in 0.5 dKH from lye will boost pH the same as 0.5 dKH from limewater.

I also believe the dry stuff is about twice as concentrated as sodium carbonate.

I would not use a stirrer for this. I would mix up a solution by hand and dose with a dosing pump.

It's more soluble though, correct? Which, from my reading, allows for a quicker and higher pH (and alk) boost than can be achieved dosing kalk.

I'm considering dosing it in small volumes to supplement kalk dosing which isn't keeping my pH where I want it. Alk is stable in the low 9 dkh with kalk at night and CaRx during the day.

 

[RSnodgrass]

You missed a previous update, I switched to a dosing pump because acrylic is not suitable at the +85% concentration I was looking to attain. Using a dosing container lacks many of the benefits of a modified stirrer but I don't have to make it.

A dosing pump is okay... it's not all its cracked up to be when controlled by the apex unless using a DOS or some other pump that resumes programming at a power loss. This is because I cut power to the pump whem pH rises and the apex lacks the fine tuning for micro dosing on its own.

Currently showing no signs of buildup like lime water and the saturation is significantly higher as well.

As such I'm dosing a fraction of what I did before and achieving the same pH boost. I'd still prefer kalk if my demand what's as high.

 

[RSnodgrass]

A lower concentration or a slower dosing pump could easily tighten this up.

Had to increase calc and MG dosing as my alk is now running 1.25 higher than previous along with pH running 0.2-0.4 higher.

 

[nereefpat]

It's more soluble though, correct? Which, from my reading, allows for a quicker and higher pH (and alk) boost than can be achieved dosing kalk.

I'm considering dosing it in small volumes to supplement kalk dosing which isn't keeping my pH where I want it. Alk is stable in the low 9 dkh with kalk at night and CaRx during the day.

Yes, you can dissolve more lye in a gallon than CaOH. If your tank consumes more alk than limewater can supply due to evaporation limits, then that might be a good reason to try it.

You missed a previous update, I switched to a dosing pump because acrylic is not suitable at the +85% concentration I was looking to attain. Using a dosing container lacks many of the benefits of a modified stirrer but I don't have to make it.

I did see the update. Looks like you've got a good system now.

As such I'm dosing a fraction of what I did before and achieving the same pH boost. I'd still prefer kalk if my demand what's as high.

To me, that's really the only problem with kalk. The limits.

A lower concentration or a slower dosing pump could easily tighten this up.

Had to increase calc and MG dosing as my alk is now running 1.25 higher than previous along with pH running 0.2-0.4 higher.

That looks pretty darn tight to me. pH swing of about 0.08?

 

[RobB'z Reef]

Pretty cool experiment! I've thought about playing with sodium hydroxide but ended up going to kalk slurry instead.