Shrimple minded Posted April 15, 2015 Report Share Posted April 15, 2015 I purchased some large black lava rocks that I intended to use in my 40G breeder Caridina setup from the following: http://www.ebay.com/...=item3f49e684a5 I boiled the rocks in tap water, rinsed for 24 hours in RO, drained, then refilled about 2 gallons of RO (pH ~6.4) to cover the rocks in a 5-gallon bucket. Over the last 6 days, I've see the TDS take an initial early rise, then drift upwards each day (albeit slowly). Start - 4 ppm TDS @12 hours - 19 ppm @4 days - 38 ppm @5 days - 44 ppm @5.5days - 49ppm I know that many of you use smaller lava rocks and consider them inert for shrimpkeeping purposes........was hoping to solicit some opinions on these rocks and their use. If I'm planning on using these rocks in a 40-gallon setup, would the TDS rise be diluted to the point that it isn't of concern? Seeing as how I'm in the initial stages of cycling and don't plan on adding shrimp for 30-60 days, should I go ahead and add the lava rocks and monitor their effects over the next month? Or would it be better to continue to soak and monitor the rocks in the 5 gallon bucket until making a decision? Should I be testing for anything additional that could be of concern "leeching" from deposits with the stones? Quote Link to comment Share on other sites More sharing options...
RyeGuy411 Posted April 15, 2015 Report Share Posted April 15, 2015 Thats kind of odd the TDS is increasing, I use lava rocks from Home Depot for barbecues and I have never noticed any TDS change in my tank. The only thing I do to prep the rocks is rinse them really well. Im sure Meta would have some specific insight into this topic. Quote Link to comment Share on other sites More sharing options...
metageologist Posted April 15, 2015 Report Share Posted April 15, 2015 No matter what rock or substrate you use the TDS will rise. With the possible exseption of a pure qruartz based rock with no inclissions. Also yes the larger the tank the less impact it will have in raising the TDS. I life TDS worked on a linier scale with a TDS of 49 in a 5 gallon bucket assume 4 gallons. Then in your 40 it would be 1.9. Now this all assumes you add no additional tds' s. Have you seen any changes in your ph, kh or gh yet. have a gneiss day Quote Link to comment Share on other sites More sharing options...
Shrimple minded Posted April 15, 2015 Author Report Share Posted April 15, 2015 Have you seen any changes in your ph, kh or gh yet. Good question. I had only been monitoring TDS, so I'm not 100% sure of my starting points, but can make some safe assumptions. I started with 0 TDS RO water, pH 7 (pH 6.4 when off-gassed for 24+ hours). I've checked all three parameters just now and pulled the following results: pH 8.0-8.2 GH 1-2 KH 2 Assuming my starting RO had 0 GH and 0 KH, I can understand that anything alkaline would cause the upward pH swing. That said, there's clearly something in the rocks that is causing all three parameters to rise. Coincidentally, I'm in the process of cycling my tank and am having to adjust pH upward because the buffering capacity of Controsoil........I was originally at pH 5.96. It actually could be helpful to add these rocks as they would slightly increase both pH and KH, which could reduce my need for baking soda........thoughts? I'm really at a loss and trying to decide if I should continue with my "testing", restart my "testing", or add the lava rocks to my cycling tank and see what shakes out. I have constant pH monitoring (Pinpoint) that would allow me to have a clearer picture of the effects of the rocks, and could do GH/KH testing several times throughout the day if so needed. Any advice is welcome, interested to hear peoples thoughts. Quote Link to comment Share on other sites More sharing options...
JamesHe Posted April 15, 2015 Report Share Posted April 15, 2015 The ration Rock/Water is high. In the tank, you never would add that many rocks, so minor TDS drifting is fine. Shrimple minded 1 Quote Link to comment Share on other sites More sharing options...
chibikaie Posted April 16, 2015 Report Share Posted April 16, 2015 Chuck 'em in the tank okay maybe not literally. Quote Link to comment Share on other sites More sharing options...
metageologist Posted April 16, 2015 Report Share Posted April 16, 2015 I would continue the testing for about 2 weeks and see where things stabilize. have a gneiss day Quote Link to comment Share on other sites More sharing options...
Desert Shrimp Depot Posted April 16, 2015 Report Share Posted April 16, 2015 I bought three orders of the black rock from that seller and use them in several of my shrimp tanks. They passed the muratic acid test - and they don't leach anything at all after initial rinsing to clean out the pores. Shrimp love to pick at the rocks as "stuff" will live in the pores. Shrimple minded 1 Quote Link to comment Share on other sites More sharing options...
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