What's this White Stuff?

[R.K. Castillo]

I've been cycling my system and the last couple of days this white stuff has showed up all over the grow media.  

What is it?

[Vlad Jovanovic]

Keep that item then. Use it to raise your carbonate hardness and your pH.

R.K. Castillo said:

Also the PH Up is the Pottasium Bicarbonate

[George]

Vlad

I sometimes hang a bag of crushed oyster shells in my fish tank.  How does that compare to using a powdered form of calcium carbonate?

thanks

[Vlad Jovanovic]

That can be a fine way to keep pH stable George. They dissolve slowly and pretty much 'when needed'...as in the shells (calcium carbonate) wont really dissolve at a pH above 7.4, and it takes some time for them to have an effect.

So, should you ever need to jack pH (or kH) up quickly for some reason, some sort of bicarbonate powder would be the way to go.

After RK takes a kH reading of his system water as is, then his source water...after which he can add that potassium bicarb...and take another kH and pH reading...hanging a bag of shell grit somewhere in his system would certainly be a good thing to do in his case...

My source water (top-ups) is quite high in calcium carbonate/bicarbonate, so I don't really want to use shell grit (and I like to run things at a lower pH than most folks), but it can be a real dandy strategy if you have soft, aggressive water...or water without much carbonate alkalinity.

[R.K. Castillo]

I've been trying to find a kH test kit around here.  Kinda hard to find.  I have found the test strips.  Are the strips acceptable (I know you said not to use them)?  If not, I will continue to look.  

Vlad Jovanovic said:

Nope. There is carbonate hardness (kH), general hardness (gH)... and total hardness. A kH reading is what you are after.

[Vlad Jovanovic]

The paper strips are usually pretty unreliable/inaccurate...but just for shits and giggles test your water and see what it says (I'm guessing you'll get a near zero reading).

Most self respecting aquarium shops/pets stores should carry the liquid drop tests (around here anyways).

[R.K. Castillo]

Okay...i'll keep looking.

[R.K. Castillo]

Just double checking.  You think the drop in PH is caused by the a low KH?  

Just a little update: I add the Pottasium Bicarb in the morning and it raises the PH but by the evening or the next morning the PH is back down to the bottom of the PH Api test kit.  

[Vlad Jovanovic]

Yup, normally what happens is that as the bacteria oxidize ammonia into nitrites/nitrates they "use up" kH and neutralize the alkaline buffer...and this causes pH to drop.

But your saying that your NO2 and NO3 numbers have always been and still are at zero...and that this pH drop is always accompanied by the white precipitates showing up at the top of your media.

That white stuff is really, really common. What's not so common is for it cause such a drastic drop in pH. So I'm guessing that your kH is super low and that it's been hot and sunny where you live.

When you add the KHCO3 what pH do you stop at?

[R.K. Castillo]

I usually stop when it gets to the top of the API Tester.  

[R.K. Castillo]

Okay...so I finally found a place that had the tester (only 30 minute drive away)  

So I tested the water in the system and that is 35.8ppm 

And the water that we use to fill up the Fish Tank comes in at 89.5

Now what should I do?

[Vlad Jovanovic]

Great. What you want to do now is forget everything you've read about pH...and jack up your kH with your potassium bicarb to about 100-150...AND NEVERMIND WHAT IT DOES TO YOUR pH...You are fishless cycling 7.8 to 8.3 is a GREAT pH for fishless cycling. (You wont be running your system forever on these numbers...just for the cycling portion of AP).

If you happen to have plants anywhere in there (and I hope to god you didn't start off with something goofy like tomatoes, peppers, cuckes...I'm gonna assume you started off with something sane like lettuce)...get some Iron Chelate (preferably Fe-EDDHA or Fe-DTPA...but use the Fe-EDTA if that's all you can find).

[R.K. Castillo]

I kept adding the Pot Bicarb until I was at 100ppm, next test a few minutes later it was at 89ppm and I kept adding and adding the Pot Bicarb and it wouldn't go any higher.  I checked 3 hours later and it is now down to 71ppm of KH.  The PH is at the top of the high pH API tester.  Any idea what's going on?