Calcium, Copper & Phosphorus

> Subject: gravel *urgh!*
> I even put a small handful of local sand blasting grit in some 
> sulfuric acid.  It bubbles for a day and stopped.  I rinsed it and 
> placed it in a cup of R.O. water and the pH stopped at 6.9-7.0.  
> Perfect I thought, but the hardness of the water rose to over 400 
> ppm, urgh!
> What's a aquatic plant lover to do?

	I believe you are using the wrong acid.  I suggest you try 
Muratic (Hydrochloric) acid next time.  The sulfuric acid turned the 
Calcium carbonate to Gypsum (Calcium sulfate).  The carbonate (CO2) 
bubbled away and the Gypsum remained behind.  In other words, the PH 
dropped, but the hardness went up.  What you need to do is to form a 
soluable Calcium salt, and the Muratic acid will do just that.  
Incidently, be sure to use the Muratic acid outside, since it has a 
horrible smell.  Also, you will need to rince the gravel very thoroughly 
afterward since the product of this reaction will be road salt instead of 


> >  Subject: Snails and Copper

> I have read that copper is really dangerous when water has very 
> little calcium(or other) hardens in it. So I wouldn't try it. Also I 

	True.  Copper tends to form an insoluable, blue carbonate in hard 
water.  It is far more soluable in soft, acid water and can rapidly 
accumulate to toxic levels.  If you accidently poison a tank, the Copper
can be removed through the use of an ion exchange resin.  Look for 
rechargable water softener "pillows" at your local aquarium store.  Table 
salt is used to "recharge" these things and they work by substituting
Sodium for Calcium, though they will also take things like Copper, Iron 
and even Lead out of your tank.  One drawback is that the Sodium level in 
the tank will rise and the Iron will be depleated as the Copper and 
Calcium are removed.  You will have to eventually replace the Iron 
manually, but a very clever route around the Sodium problem is to 
recharge the pillows with Potassium, rather than Sodium chloride.  In 
this case, the pillow will substitute Potassium for Copper, and Potassium 
is far better for the plants than Sodium.  The above will work very 
effectivly as an emergency measure whether one uses Sodium or Potassium.  
Just remember to wash all the salt solution out of the pillow before 
putting it back in the tank.


> Subject: Phosphates/Chemistry
>   Yes, we monitor phosphate, so as to limit
>           corrosion in the water system.  Orthophosphate is held at
>           approximately 2 mg/l.
> Could someone tell me what this means?  Is this good or high.  If high,
> what do I do.  I've read somewhere that excess phosphate can render
> (liquid) iron fertilization nearly useless.  Is this true?


	Probably.  Iron phosphate isn't particularly soluable, so I would 
expect excessivly high phosphate levels to decrease things like Iron and 
Calcium in solution (see Copper carbonate above).  Despite this, I think 
you have nothing to worry about.  2 mg/l is very low (2 PPM methinks..).  


		Roger L. Sieloff