total dissolved solids
...that total dissolved solids, a class of water pollutants, is useful as an indicator of aquatic biota health, yet harmful to the plumbing of aquaria and hot tubs? 
...that <b id="mwCKk"><a href="./Total_dissolved_solids" id="mwCKo" rel="mw:WikiLink" title="Total dissolved solids">total dissolved solids</a></b>, a class of <a class="mw-redirect" href="./Water_pollutant" id="mwCKs" rel="mw:WikiLink" title="Water pollutant">water pollutants</a>, is useful as an indicator of <a class="mw-disambig" href="./Aquatic" id="mwCKw" rel="mw:WikiLink" title="Aquatic">aquatic</a> <a class="mw-disambig" href="./Biota" id="mwCK0" rel="mw:WikiLink" title="Biota">biota</a> health, yet harmful to the <a href="./Plumbing" id="mwCK4" rel="mw:WikiLink" title="Plumbing">plumbing</a> of <a class="mw-disambig" href="./Aquaria" id="mwCK8" rel="mw:WikiLink" title="Aquaria">aquaria</a> and <a href="./Hot_tub" id="mwCLA" rel="mw:WikiLink" title="Hot tub">hot tubs</a>? <i id="mwCLE">(pictured: water with dissolved solids)</i>