I'm setting up a 90 gallon tank where I would like to plumb in automatic water changes. The local water supply engineer assured me that only free chlorine is added to the water (not chloramine). The water quality report says the average concentration is 0.7ppm, ranging 0.2 to 1.1 ppm. Interestingly, water hardness is stated as 63ppm with a high variance.
To deal with the chlorine in an automated way, I'm seeing several options:
1. keep a reserve tank with floats and pumps and so forth so that water can collect and off-gas the chlorine. A one-time investment but multiple failure points and a clutter.
2. Install an RO unit which has a reserve tank anyhow. So I'm not seeing this as a better alternative. And these filters seem to require prefilters anyhow including activated carbon, so this method seems overly expensive and duplicates other methods. Also the flow rate is reduced, if I understand correctly. That's a lot of effort and expense (including periodic replenishment of prefilters) just to remove chlorine. It also softens the water, not sure I care about that.
3. Install a conventional inline under-sink activated carbon filter. The performance data sheets on these suggest that they treat 1000 gallons or so. Weekly changes of 50 gallons would suggest that a cartridge would be spent after 20 weekly water changes, or about 5-6 months. Same math if 50% water change is spread out over a week. New charcoal cartridges are $30-$90, who knows what explains the variance.
4. Use an automatic doser to add dechlorinator just after the automated water change completes. This involves an initial investment similar to above options but a monthly expense to purchase the dechlorinator. This method has the advantage of removing chloramine just in case the water supply changes methods without telling us. The API tap water dechlorinator treats nearly 4800 gallons, for about $14. So a 50% water change (45 gallons) per week would last nearly two years. This seems like the most elegant and cost-effective solution. One issue is that we would need to be sure that the dechlorinator is not one which requires shaking of the bottle.
5. Do nothing. By changing out 10% of the water, the chlorine level in the tank would be 1/10 of the tap water or about 0.1ppm. The question is how fast would this off-gas? Would it slowly accumulate with each daily water change? In a 78-degree tank, wouldn't the chlorine be gone by the next day?
Am I thinking about these options clearly? I'm leaning toward option 5; if monitoring shows accumulation of chlorine I can add the autodose of dechlorinator.
To deal with the chlorine in an automated way, I'm seeing several options:
1. keep a reserve tank with floats and pumps and so forth so that water can collect and off-gas the chlorine. A one-time investment but multiple failure points and a clutter.
2. Install an RO unit which has a reserve tank anyhow. So I'm not seeing this as a better alternative. And these filters seem to require prefilters anyhow including activated carbon, so this method seems overly expensive and duplicates other methods. Also the flow rate is reduced, if I understand correctly. That's a lot of effort and expense (including periodic replenishment of prefilters) just to remove chlorine. It also softens the water, not sure I care about that.
3. Install a conventional inline under-sink activated carbon filter. The performance data sheets on these suggest that they treat 1000 gallons or so. Weekly changes of 50 gallons would suggest that a cartridge would be spent after 20 weekly water changes, or about 5-6 months. Same math if 50% water change is spread out over a week. New charcoal cartridges are $30-$90, who knows what explains the variance.
4. Use an automatic doser to add dechlorinator just after the automated water change completes. This involves an initial investment similar to above options but a monthly expense to purchase the dechlorinator. This method has the advantage of removing chloramine just in case the water supply changes methods without telling us. The API tap water dechlorinator treats nearly 4800 gallons, for about $14. So a 50% water change (45 gallons) per week would last nearly two years. This seems like the most elegant and cost-effective solution. One issue is that we would need to be sure that the dechlorinator is not one which requires shaking of the bottle.
5. Do nothing. By changing out 10% of the water, the chlorine level in the tank would be 1/10 of the tap water or about 0.1ppm. The question is how fast would this off-gas? Would it slowly accumulate with each daily water change? In a 78-degree tank, wouldn't the chlorine be gone by the next day?
Am I thinking about these options clearly? I'm leaning toward option 5; if monitoring shows accumulation of chlorine I can add the autodose of dechlorinator.
