Might purple up have a positive effect other than adding (inert) alk / Ca?

UK_Pete · Dec 30, 2014

Interesting thanks. I have some coralline in my tank, on rocks, but I want it to spread to the walls etc. But despite the params being good, its not spreading. Which is why I wondered about the purple up, as I say I've heard its snake oil but on the other hand I've read a lot of anecdotes that it works. Hence my OP. As I said above I have started dosing small amounts of kalk suspension so will give it a couple of weeks (maybe 4) to see if I get any spots of coralline start on the walls or egg crate. I've had it before when I dosed kalk but not much, and I didn't test all my params then so I dont know if I had super high alk. I was just wondeirng really if there might be an alternative explantion to its alleged effects on coralline, I can't see the stuff adding calcium or alk because its chemistry seems to not suit that task, as well as the fact that I can maintain Ca and alk perfectly well with 2 part. But despite that no coralline growth. I wonder though if adding coraline scrapings would work, although many people seem to get coralline without that, but its interesting that scrapings worked for you. Not much seems to be known as to how coralline spreads (via spores or some other means etc) which makes it hard to know what to do.

Big Larr · Dec 30, 2014

From what I've experienced always add scrapings of it but turn your syphon off for the sump so it blows around the tank and not sucked into the sump filter

Big Larr · Dec 30, 2014

I have not been able to get purple coraline without adding some first just my experience

Cory · Dec 30, 2014

Mine is starting to grow under a rock on the glass in the shaded area. Spots appearing there. Strange thing is in my sump I've got a 9led red/blue plant grow bulb and its growing there on the glass. On the tank I use led too (Kessil), which I just changed from a Chinese blue/white led.

I wonder if corraline loves red spectrum and red seems to penetrate or get to the shadowed areas more?

Big Larr · Dec 31, 2014

Probably does and algae does love red spectrum

UK_Pete · Dec 31, 2014

Interesting obs there, I have noticed in the past sometime coralline does seem to like more shaded areas, and other times in other tanks its growing in full strength lighting, even during different periods in my own tanks in the past, and likewise some people say it likes shade, others say it likes good light, probably because of that effect. I have a feeling its to do with the nutrient profile like with corals, ie maybe in higher nutrient water it likes more shade, perhaps because it gets too much competition from other algaes for instance (or the other way round, I never checked params of tanks I observed personally).

Randy Holmes-Farley · Dec 31, 2014

I think there are many different species of coralline that prefer different lighting intensities.

UK_Pete · Dec 31, 2014

Ah that would make sense Randy I see what you mean. Is coralline actually a coral or an algae? I guess its an algae like halemedia (not sure the spelling there) but I'm not sure, it seems much more sensitive than halemedia.

Randy Holmes-Farley · Dec 31, 2014

It's an algae, not a coral.

UK_Pete · Dec 31, 2014

"Remember kids, there are no stupid questions, just stupid people"... doh.

Anyway moving swiftly on, I am seeing too much alk rise from adding kalk powder as I have been doing for a couple of days, so I was wondering if I add 1 mole of sodium bicarbonate to 1 mole of calcium hydroxide in a small amount of water, will I end up with a mole of calcium carbonate and a mole of sodium carbonate? I think that the bicarb will give up a CO2 molecule to the hydroxide but I'm not sure. I want to convert the kalk to calcium carbonate. Since the sodium carbonate is more soluble I am hoping I can filter the solution from the solid calcium carbonate precipitate.

Cheers, Pete

Randy Holmes-Farley · Dec 31, 2014

You may end up with mostly calcium carbonate and sodium hydroxide. Each calcium hydroxide has two hydroxide in it.

UK_Pete · Jan 1, 2015

OK thanks Randy. Would 2 moles of sodium bicarb be right? I was trying to work it out and I came up with this:

2NaHCO3 + Ca(OH)2 -> Na2CO3 + 2H2O+ CaCO3

But the reaction would proceed even if the kalk was in solid particles? I'm not sure how much the bicarbonate disassociates once in water, I guess the carbonate needs to be in the form of carbonic acid for it to react with the particles of calcium hydroxide if I want them to be converted 'in place' into particles of carbonate?

Randy Holmes-Farley · Jan 1, 2015

How much either of the added ingredients dissolve depends on the concentration.

The equation seems right. The pH will be high enough that, if allowed it, it will suck in more CO2 from the air to make some bicarbonate from the carbonate.

Cory · Jan 4, 2015

Since I've been raising my salinity to nsw values corraline in my sump has started to take off under the red/blue led. The only difference I see now besides raising salinity is that the alkalinity is reaching 10dkh and calcium 480ppm rather than 7dkh and 400ppm calcium. I don't add any purple up nor do I have sand.